Alpine Mass Movements: Implications for hazard assessment and ...

Alpine Mass Movements: 

Implications for hazard 

assessment and mapping 

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Inhalt 

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Florian Rudolf-Miklau, Richard Bäk, Franz Schmid, Christoph Skolaut: 

Hazard Mapping for Mass Movements: Strategic Importance and 

Transnational Development of Standards in the ASP-Project ADAPTALP 

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Imprint / Disclosure 

Federal Ministry of Agriculture, Forestry, Environment and Water Management, 

Marxergasse 2, 1030 Vienna, Austria. 

Verein der Diplomingenieure der Wildbach- und Lawinenverbauung, 

Bergheimerstrasse 57, 5021 Salzburg, Austria 

Editorial Team: 

Florian Rudolf-Miklau, Richard Bäk, Christoph Skolaut and Franz Schmid 

Florian Rudolf-Miklau: 

Principles of Hazard Assessment and Mapping 

Richard Bäk, Hugo Raetzo, Karl Mayer, 

Andreas von Poschinger, Gerlinde Posch-Trözmüller: 

Mapping of Geological Hazards: Methods, Standards and 

Procedures (State of Development) - Overview 

Mateja Jemec & Marko Komac: 

An Overview of Approaches for Hazard Assessment 

of Slope Mass Movements 

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Coordination: 

Barbara Kogelnig-Mayer 

Layout: 

Studio Kopfsache, Mondsee 

Cite as: 

BMLFUW (2011): Alpine Mass Movements: Implications for hazard assessment 

and mapping, Special Edition of Journal of Torrent, Avalanche, Landslide and 

Rock Fall Engineering No. 166. 

This publication was implemented within the framework of EU-project 

AdaptAlp, Workpackage 5, and is co-financed by the European Regional 

Development Fund (ERDF) 

BLOCK 1: Key-note papers 

Roland Norer: 

Legal Framework for Assessment and Mapping of Geological Hazards 

on the International, European and National Levels 

Karl Mayer, Bernhard Lochner: 

Wolfram Bitterlich: 

Internationally Harmonized Terminology for 

Wildbachverbauung und Ökologie Widerspruch oder sinnvolle Ergänzung? 

Geological Risk: Glossary (Overview) 

Michael Mölk, Thomas Sausgruber, Richard Bäk, Arben Kociu: 

Standards and Methods of Hazard Assessment for 

Rapid Mass Movements (Rock Fall and Landslide) in Austria 

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Hugo Raetzo, Bernard Loup: 

Geological Hazard Assessment in Switzerland 

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Cover picture: Großhangbewegung Rindberg, Gde. Sibratsgfäll, Vorarlberg 

Source: die.wildbach 

BLOCK 2 

Stefano Campus: 

Landslide Mapping in Piemonte (Italy): 

Danger, Hazard & Risk 

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Inhalt 

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Marko Komac, Mateja Jemec: 

Standards and Methods of Hazard Assessment 

for Rapid Mass Movements in Slovenia 

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BLOCK 2: Hazard assessment and mapping of mass-movements in the EU 

Karl Mayer, Andreas von Poschinger: 


Geological Dangers (Mass Movements) in Bavaria 

Didier Richard: 


for Rapid Mass Movements in France 

Pere Oller, Marta González, Jordi Pinyol, Jordi Marturià, Pere Martínez: 

Goeohazards Mapping in Catalonia 

Claire Foster, Matthew Harrison & Helen J. Reeves: 


Mass Movements in Great Britain 

Karl Mayer, Bernhard Lochner: 

International Comparison: Summary of the Expert 

Hearing in Bolzano on 17 March 2010 

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Zusammenfassung: 

Massenbewegungen (Steinschlag, Rutschungen, Felsgleitungen) bedrohen den alpinen 

Lebensraum und verursachen zahlreiche Risiken. Durch die intensive Raumnutzung in den 

Bergtälern besteht ein zunehmender Bedarf an genauen Gefahrenkarten für diese Gefahrenarten. 

Aufgrund fehlender Daten und zuverlässiger Methoden für die Gefahrenbeurteilung 

wurden bisher keine generellen Standards für die Gefahrdarstellung von Rutschungen und 

Steinschlägen entwickelt. Die Unsicherheit in der Beurteilung der Gefahren wird durch den 

Einfluss des Klimawandels noch erhöht. Das Projekt ADAPTALP zielt darauf ab, diese Lücke 

durch die Entwicklung transnationaler Standards für die Gefahrenzonenplanung für Massenbewegungen 

zu schließen. 

FLORIAN RUDOLF-MIKLAU, RICHARD BÄK, FRANZ SCHMID, CHRISTOPH SKOLAUT 

Hazard Mapping for Mass Movements: 

Strategic Importance and Transnational Development 

of Standards in the ASP-Project ADAPTALP 

Gefahrendarstellung von Massenbewegungen: 

Strategische Bedeutung und länderübergreifende 

Entwicklung von Standards im Projekt ADALPTALP 

Summary: 

Mass movements (rock falls, landslides, rock slides) are major threats for the Alpine living 

space and cause various risks. Due to the intensive land use in the mountain valleys, there is 

an urgent need for reliable hazard maps for these types of hazards. Missing data and the lack 

of reliable methods for the assessment of hazards has obstructed the development of general 

standards in hazard mapping for landslides and rock fall. The uncertainties and inaccuracies 

of models are increased by the impact of climate change. The project ADAPTALP (within the 

Alpine Space Program) aims to close this gap by creating transnational standards for hazard 

mapping concerning geological risks (mass movements). 

Alpine Space at risk: Importance of hazard maps 

In the Alpine countries, natural hazards constitute 

a security risk in many regions. Floods, debris 

flows, avalanches, landslides and rock falls 

threaten people, their living environments, their 

settlements and economic areas, transport routes, 

supply lines, and other infrastructure. They 

constitute a major threat to the bases of existence 

of the population. The increasing settlement 

pressure and area consumption, the opening up 

of transport routes in the Alps as well as strong 

growth rates in tourism have brought about a 

considerable spatial extension of endangered 

areas. With the rising demands on welfare and 

quality of life, the need for safety and protection 

of the population increased as well. 

Hazard maps that show areas at risk by natural 

hazards are of paramount importance for the 

development of Alpine regions. The maps count 

among the active planning measures in natural 

hazard management and serve to the safety of 

existing settlements and their inhabitants as 

well as to the steering of land-use only outside 

of endangered areas. Since the beginning of 

1970’s, these maps have been established in 

several countries (Switzerland, Austria, France) 

for the hazards “flood”, “debris flow” and 

“snow avalanches”. However there are no legal 

(technical) standards available for the outline 

of areas endangered by mass movements (e.g. 

landslides, rock fall). The assessment of these 

processes concerning the frequency and intensity 

of events (disasters) is difficult and demanding 

due to the lack of measurements and basic data. 

In addition, the knowledge of geotechnical 

parameters, physical properties and triggering 

mechanisms of the displacement processes still 

are fragmentary, although wide progress were 

achieved by improved monitoring methods and 

the detailed analysis of past events. 

Recently the expansion of settlement areas 

in Alpine valleys and the growing vulnerability of 

human facilities have significantly increased the risk 

for natural disasters caused by mass movements. 

The growing demand for hazard maps that cover 

these risky processes has initiated strong efforts in all 

mountainous countries in Europe to develop exact 

methods and appropriate standards that enable the 

production of hazard maps for mass movements 

with sufficient accuracy. By bundling these initiatives 

the ASP (Alpine Space Program/Funding Initiative of 

the European Commission) project ADAPTALP – in 

cooperation with other projects like SAFELAND, 

PERMANET or MASSMOVE – aims at the 

development of technical standards and provision 

of harmonized quality criteria for all member states.

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Mass movements: Hazard processes on slopes 

A variety of processes exist by which materials 

can be moved through the slope system. These 

processes are generically known as mass 

movement or mass wasting. Mass movements 

per definition are movements of bodies of soil, 

sediments such as residual soil and bed rock 

which usually occur along steep-sided slopes and 

mountains. Mass movements can be classified 

due to the rate of movement (rapid or slow), the 

type of movement (falling, sliding or flowing) and 

to the type of material involved (soil, sediments or 

rock debris). 

Fig. 1: Land slide in cohesive soil resulting from slope 

instabilities and saturation of material by water. 

Abb. 1: Rutschung in bindigem Boden resultierend aus 

Hanginstabilitäten und Wassersättigung des Bodens. 

Mass movements have direct and 

indirect impact on a number of human activities. 

The steepness and structural stability of slopes 

determines their suitability for agriculture, forestry, 

and human settlement. Instable slopes can also 

become a hazard to humans if their materials 

move rapidly through the process of mass wasting. 

Landslides can suddenly rush down a steep slope 

causing great destruction across a wide area 

of habitable land and sometimes also floods by 

damming up bodies of water. Expenses related to 

landslides include actual damages to structures 

or property, as well as loss of tax revenues on 

devalued properties, reduced real estate values 

in landslide prone areas, loss of productivity of 

agricultural lands affected by landslides, and loss 

of industrial productivity because of interruption 

of transportation systems by landslides. Not only 

rapid types of mass movements are harmful. 

Slow movement of creep does more long term 

economic damage to roads, railroads, building 

structure and underground pipes. 

The operation of mass movement 

processes relies upon the development of 

instability in the slope system. The predominant 

source of stress is the gravitational force. Other 

factors that affect mass movements are the 

steepness of slopes, the lithological property of 

the slope materials, and the amount of water in 

the material. The two most important parameters 

in mass movement is the angle of friction and the 

cohesion. 

The magnitude of the gravitational 

force is related to the angle of the slope and the 

weight of slope sediments and rock. The following 

equation models this relationship: 

F = W sin Ø 

where 

F is gravitational force, 

W is the weight of the material occurring at 

some point on the slope, and 

Ø is the angle of the slope. 

The stability of a slope depends on the 

relationship between the stresses applied to the 

materials that make up the slope and their internal 

strength. Mass movement occurs when the stresses 

exceed the internal strength. Slopes composed of 

loose materials, such as sand and gravel, derive 

their internal strength from frictional resistance, 

which depends on the size, shape, and arrangement 

of the particles. Slopes consisting of silt and clay 

particles obtain it from particle cohesion, which is 

controlled by the availability of moisture in the soil. 

Rock slopes generally have the greatest internal 

strength due to the crystalline structures. 

Instability is not always caused by an 

increase in stress. In some cases, the internal 

strength of the materials can be reduced resulting 

in the triggering of a mass movement. Failure of 

the slope material can occur over a range of time 

scales. Some types of mass movement involve 

rather rapid, spontaneous events. Sudden failures 

tend to occur when the stresses exerted on the 

slope materials greatly exceed their strength for 

short periods of time. Mass movement can also 

be a less continuous process that occurs over long 

periods of time. Slow failures often occur when 

the applied stresses only just exceed the internal 

strength of the slope system. 

Many factors can act as triggers for slope 

failure. One of the most common is prolonged 

or heavy rainfall. Rainfall can lead to mass 

movement through three different mechanisms. 

Often these mechanisms do not act alone. The 

saturation of soil materials with water increases 

the weight of slope materials which then leads 

to greater gravitational force. Saturation of soil 

materials can also reduce the cohesive bonds 

between individual soil particles resulting in the 

reduction of the internal strength of the slope. 

Lastly, the presence of bedding planes in the slope 

material can cause material above a particular 

plane below ground level to slide along a surface 

lubricated by percolating moisture. 

Additionally, a large variety of other 

trigger mechanism for mass movement other than 

the gravitational are known, such as: 

• Earthquake shocks cause sections of 

mountains and hills to break off and slide 

down. 

• Human modification of the land or 

weathering and erosion help loosen large 

chunks of earth and start them sliding 

downhill. 

• Vibrations from machinery, traffic, weight 

loading from accumulation of snow, 

stockpiling of rock, from waste piles and 

from buildings and other structures. 

In the Alps, mass movements occur in a wide 

range of processes consisting of bedrock and soil 

or a mixture of both. 

Mass movement on hard rock slopes 

is often dramatic and quick. They involve the 

downward movement of small rock fragments 

pried loose by gravitational stress, the enlargement 

of joints during weathering and/or freeze-thaw 

processes (rock fall). Larger scale, down slope 

movement of rock can also occur along welldefined 

joints or bedding planes. This type of 

movement is called rock slide. Rock slides often 

occur when a fracture plane develops causing 

overlying materials to slide down slope. 

Slopes formed from clays and silt 

sediments display somewhat unique mass 

movement processes. Two common types of 

mass movements in these cohesive materials are 

rotational slips (slumps) and mudflows. Both of 

these processes occur over very short time periods. 

Rotational slips or slumps occur along clearly 

defined planes of weakness which generally have 

a concave form beneath the earth's surface. These 

processes can be caused by a variety of factors. 

The most common mechanical reason for them 

to occur is erosion at the base of the slope which 

reduces the support for overlying sediments. 

Mudflows occur when slope materials become 

so saturated that the cohesive bonds between 

particles is lost. In a mudflow there is enough 

water to allow the mixture to flow easily, as a 

viscous stream. Mudflows can occur on very low 

slope angles because internal particle frictional 

resistance and cohesion is negligible.

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Type 

Fall 

Topple 

An earth flow is slower moving than a mudflow 

and involves a mass of material that retains rather 

distinct boundaries as it moves. “Debris flow” is 

a term used generally for rapid mass movements 

consisting of water and residual soil. The term 

implies a heterogeneous mixture of materials 

including a considerable fraction of particles 

that are coarser than the particles in mud. Debris 

flows occur on slopes as well as in laterally 

confined channels. 

Bedrock 

Rock fall 

Rock 

avalanche 

Rock 

topple 

Engineering soil 

predominantly … 

… coarse 

(Debris fall) 

(Debris 

topple) 

… fine 

(Earth fall) 

(Earth topple) 

Slide Rock slide Debris slide Earth slide 

Spread 

Flow 

Rock 

spread 

(Rock 

flow) 

(Debris 

spread) 

Debris flow 

(in channels) 

(Earth spread) 

Earth flow 

Tab. 1: Types of mass movements (classification) after 

Raetzo. 

Tab. 1: Typen von Massenbewegungen (Klassifikation) 

ASP-project ADAPTALP: Adaptation of 

natural hazard management to climate change 

Climate change is, to a large extent, constituted by 

increasing temperatures and changed precipitation 

patterns. Any change of these critical factors 

has implications on the frequency and extent of 

natural hazards including mass movements. A 

major impact on the intensity of mass movements 

at high altitudes (above 2300 m in the Alps) has 

thaw of permafrost and the retreat of glaciers due 

to the increasing temperatures. The uncertainties 

and the increase of natural hazards due to the 

impacts of climate change require concerted 

management in the Alpine Space. It must be 

managed on a transnational, national, regional 

and local scale to effectively save human life, 

settlements and infrastructure. Nevertheless, there 

is still a lack of precise data taking climate change 

into account. The result is an insufficient accuracy 

of available models and inaccurate prediction of 

natural hazard and menacing catastrophic events. 

The impact of climate change increases these 

uncertainties. 

Harmonized cross-sectoral hazard 

assessment and hazard mapping must be balanced 

on a transnational level. The ADAPTALP project 

(www.adaptalp.org) focuses on the harmonization 

of the various national approaches and methods 

for the assessment of hazards related to mass 

movements. Along with the harmonization 

of terminology, an important issue tackled by 

ADAPTALP is the provision of reliable data and 

models for this kind of processes. The more 

reliable the information basis, the more efficiently 

adaptation strategies on local and regional level 

can be implemented. The project is based on an 

integrated transnational approach. That means 

that a comprehensive comparison of all available 

standards and methods is carried out covering all 

countries in the Alpine region (Austria, Germany, 

Italy, France, Switzerland, Slovenia) and other 

European states with a considerable share of 

mountain regions (Great Britain, Spain, Norway). 

The transnational exchange of knowledge and 

the international harmonization in method and 

procedure will raise the quality of hazard assessment 

considerably. A general “state-of-the-art” for hazard 

mapping concerning mass movements seems to be 

within reach. 

Fig. 2: Transnational standards in hazard mapping are of major importance for the prevention of 

catastrophic events according to land use in endangered areas. 

Abb. 2: Die Entwicklung von länderübergreifenden Standards in der Gefahrendarstellung ist bei 

der Prävention von Katastrophenereignissen von großer Bedeutung, da gefährdete Gebiete immer 

stärker genutzt werden. 

Hazard maps for mass movements 

Hazard zones are designated areas threatened 

by natural risks such as avalanches, landslides or 

flooding. The formulation of these hazard zones is 

an important aspect of spatial planning. The basis 

for hazard maps is a comprehensive assessment 

of geological and hydro(geo)logical framework 

conditions, slope instabilities, relevant triggering 

mechanisms, properties of displacement 

processes, potential risks and the vulnerability 

of endangered areas (objects). Consequently it is 

essential to distinguish the three aspects of mass 

movement assessment and mapping: 

• Dangers (susceptibilities): Assessment 

and characterization of threat (typology, 

morphology, inventory of mass movements). 

• Hazards: Spatial and temporal probability, 

intensity and forecasting of evolution 

(scenarios) are needed. 

• Risks: Interaction between a threat having 

particular hazard and human activities. 

In principle, these theoretical concepts are well 

known by experts but 

may cause problems in 

practice when applied 

in a legal framework. 

It is not unusual for 

unsuitable types of 

hazard maps to be 

applied for the wrong 

purposes. For example 

it is often to find 

landslide inventory 

maps used as hazard 

or risk maps. 

When mapping 

geological hazards 

(mass movements) in 

principle we have to 

distinguish between two situations: 

1. Scientific studies on mass movements with no 

legal implications (e.g. on land use planning): 

Typical cases are studies carried out by 

universities (research institutes). The aim of 

these studies is to understand the mechanical 

features of instability or to study different ways of 

evolution of the phenomenon (scenarios) in order 

to assess the susceptibility of investigated areas. 

Landslide inventories can be made by means of 

a historical or morphological approach. 

2. Susceptibility/Hazard index/Hazard maps that 

have direct (obligatory) consequences for land 

use planning and building trade at different 

scale: The scale used to present the results of 

the hazard assessment depends on the desired 

product (susceptibility map, hazard index map, 

hazard zone map) and must be balanced with 

the precision requirements according to the 

spatial level of application (supra-regional, 

regional, local). The legal significance of these 

maps requires technical standards and a “stateof-the-art” 

concerning formal requirements 

(e.g. investigation methods, documentation),

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hazard assessment and procedures of the check 

and approval of the maps. 

ADAPTALP (in Work Package 5) will 

evaluate, harmonize and improve different 

methods of hazard mapping applied in the Alpine 

area. A main emphasis will be on a comparison 

of methods for mapping geological hazards in 

the individual countries. A glossary will facilitate 

interdisciplinary and multilingual cooperation as 

well as support the harmonization of the various 

methods. In selected model regions methods 

to adapt risk analysis to the impact of climate 

change will be tested. This should support the 

development of hazard zone planning towards 

Fig. 3: Example for a susceptibility map of the Arlberg region 

(Vorarlberg/Austria) after Ruff 

Abb. 3: Beispiel einer Suszeptibilitätskarte der Arlbergregion 

(Vorarlberg/Österreich) nach Ruff 

a climate change adaptation strategy. The results 

will be summarized in a synthesis report. 

These fields of research within the 

project contain the topics to work out the 

“minimum standards” (minimal requirements) for 

the creation of danger (susceptibility) and hazard 

maps for landslides. The first step is the evaluation 

of the “state of the art” in hazard mapping in each 

involved country. Two main questions will be 

answered by the project: 

• What kinds of danger (susceptibility), 

hazard and risk maps are officially applied 

in each country? 

• Which standards are these maps based on? 

The second step will be the “harmonization” of 

the different methods, which are used in several 

countries. Therefore similarities should be worked 

out and the “least common denominator” in the 

methods of hazard mapping should be found. 

The final step will be the creation of guidelines 

and recommendation, which include the results 

of this “harmonization”. They will include 

“minimum requirements for the creation of danger 

(susceptibility), hazard and risk maps”. 

Other important results – developed in cooperation 

with other projects as MASSMOVE – will be: 

• Definition of minimal requirements for the 

collection of the relevant data of endangered 

areas and cartographic representation of 

slides and rock falls. 

• Specification of minimal requirements for 

the spatial description of the dangers. 

• Development of minimal requirements for 

the determination of the hazard potential of 

slides and rock falls. 

• Development of tools for the reduction of 

the risk potential by consideration of the 

hazards during land use planning by the 

local administrations and during the land 

use as well as for the planning of preventive 

measures. 

Anschrift der Verfasser / Authors’ addresses: 

DI Dr. Florian Rudolf-Miklau 

Bundesministerium für Land- und Forstwirtschaft, 

Umwelt und Wasserwirtschaft, 

Abteilung IV/5, Wildbach- und Lawinenverbauung 

Federal Ministry for Agriculture, Forestry, 

Enviroment and Water Management, 

Department IV/5, Torrent and Avalanche Control 

1030 Wien, Marxergasse 2 

Tel.: (+43 1) 71 100 - 7333 

FAX: (+43 1) 71 100- 7399 

Mail: florian.rudolf-miklau@lebensministerium.at 

Homepage: http://www.lebensministerium.at/forst 

Dr. Richard Bäk 

Amt der Kärntner Landesregierung, Abt. 15 Umwelt 

Unterabteilung Geologie und Bodenschutz, 

A – 9020 Klagenfurt, Flatschacher Straße 70 

Tel: +43 - (0) 50536 - 31510 

Fax: +43 - (0) 50536 - 41500 

Mob. +43 - (0) 664 - 8053631510 

Mail: richard.baek@ktn.gv.at 

DI Franz Schmid 


Umwelt und Wasserwirtschaft, 

Abteilung IV/5, Wildbach- und Lawinenverbauung 


Enviroment and Water Management, Department 

IV/5, Torrent and Avalanche Control 


Tel.: (+43 1) 71 100 - 7338 

FAX: (+43 1) 71 100- 7399 

Mail: franz.schmid@lebensministerium.at 


DI Christoph Skolaut 

Wildbach- und Lawinenverbauung, 

Sektion Salzburg 

Torrent and Avalanche Control, District Salzburg 

5020 Salzburg, Bergheimerstraße 57 

Tel.: (+43 662) 871853 – 303 

FAX: (+43 662) 870215 

Mail: christoph.skolaut@die-wildbach.at 


Literatur / References: 

BATES A. L., JACKSON J. A.: 

Glossary of Geology. American Geological Institute, 3rd Edition, 1987. 

CAMPUS S., BABERO S., BOVO S., FORLATI F. (EDS.): 

Evaluation and prevention of natural risks. Taylor and Francis/Balkema, 

2007. 

GLADE T., ANDERSON M., CROZIER M. J. (HRG.): 

Landslide Hazards and Risk. John Wiley & Sons, Chichester, 2005. 

GRUNER U., WYSS R.: 

Anleitung zur Analyse von Rutschungen. Swiss Bull. angew. Geol., Vol. 

14/1+2, 2009. 

RAETZO, H. , RICKLI, C.: 

Rutschungen. In: Bezzola G.R, & Hegg, C. (Hrsg.) 2007: Ereignisanalyse 

Hochwasser 2005, Teil 1 – Prozesse, Schäden und erste Einordnung. 

Bundesamt für Umwelt BAFU, Eidgenössische Forschungsanstalt WSL. 

Umwelt-Wissen Nr. 0707, 2007. 

RUFF, M.: 

GIS-gestützte Risikonanalyse für Rutschungen und Felsstürze in den 

Ostalpen (Vorarlberg, Österreich). Georisikokarte Vorarlberg. Diss. Univ. 

Karlsruhe, 2005. 

SIDLE R. C., OCHIAI H.: 

Landslides processes, prediction and land use. American Geographical 

Union, water resources monograph 18, Springer Verlag, 2006.

Key-note papers 

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FLORIAN RUDOLF-MIKLAU 

Principles of Hazard Assessment and Mapping 

Grundlagen der Analyse und 

Bewertung von Naturgefahren 

Summary: 

The article summarizes the general principles for the assessment of natural hazards. The 

main emphasis lies on the basic approaches and methods of hazard assessment with special 

attention to the “frequency-intensity-concept” (including the deficits of this approach). The 

strategic importance of “preventive” planning with regards to the use and development of 

endangered areas in mountain areas is discussed. In addition, a summary of the most important 

standards and categories of hazard (risk) mapping is provided. 


Der Beitrag fasst die generellen Grundlagen der Analyse und Bewertung von Naturgefahren 

zusammen. Der Schwerpunkt liegt im Bereich der grundlegenden Ansätze und Methoden für 

die Gefahrenbewertung, wobei das „Häufigkeits-Intensitäts-Konzept“ besondere Beachtung 

findet (einschließlich der Defizite dieses Ansatzes). Weiters wird auf die strategische Bedeutung 

der „präventiven Planung“ hinsichtlich der Nutzung und Entwicklung von gefährdeten 

Gebieten im Gebirge eingegangen. Abschließend erfolgt eine zusammenfassende Darstellung 

der wichtigsten Standards und Kategorien der kartographischen Darstellung von Naturgefahren. 

Basic concept of hazard assessment 

Effective prevention against natural hazards 

requires a better understanding of the processes 

occurring in nature. The primary aim of hazard 

assessment is to gain a deep and comprehensive 

knowledge of these processes in order to provide 

accurate prognosis of the expected magnitude 

of hazardous events and the corresponding 

damaging effects. (RUDOLF-MIKLAU in SUDA 

ET. AL., 2011 [18.]) Another important demand 

is the prediction of the time of occurrence and 

duration of a catastrophic event (predictability 

and advanced warning time; Fig. 1) (RUDOLF- 

MIKLAU, 2009 [14.]). The initial purpose of 

hazard assessment is the provision of basic 

knowledge for the planning of protection 

measures (e.g. flood control, avalanche control), 

which requires quantitative information about 

the order and magnitude of catastrophic events 

and their probable damaging consequences on 

human health, economic activities, environment, 

and cultural heritage. 

Predictability 

Earthquake 

Rockfall 

seconds 

According to the well-established basic concept of 

hazard assessment, the procedure can be divided 

in three distinct steps (HÜBL ET AL., 2007 [9.]: 

• The survey of basic information (data) 

• The analysis of hazards (and risks) 

• The valuation of hazards (and risks) 

As a rule, the survey of information related to 

natural hazards focuses on the acquisition of 

basic data on relevant factors in nature. The survey 

includes “geo-data” (topography, geology, and 

soil), “meteo-data” (climate, weather), “hydrodata” 

(precipitation, run-off, and groundwater) 

and “eco-data” (environmental parameters). In 

addition, data on past (historic) events represent a 

major source of information. (RUDOLF-MIKLAU, 

2009 [14.]) For the purpose of risk assessment, 

data for natural processes must be combined with 

data related to human activities. These sources of 

information include demographic and economic 

statistics, data on land use and agriculture, 

and records of damages caused by past events 

(BRÜNDL ET AL., 2009 [5.]). 

Drought 

Debris flow 

Floods 

Storm 

Wildfire 

Volcanism 

Deceases 

Avalanches 

Landslides 

minutes hours days weeks 

Fig. 1: Predictability of natural hazards (RUDOLF-MIKLAU, 2009 [14.]). 

Abb. 1: Vorhersagbarkeit von Naturgefahren (RUDOLF-MIKLAU, 2009 [14.]). 

Advanced warning time(T)


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Management Presentation Validation Survey 

HAZARDS 

Hazard analysis 

Localization and topography 

Triggering mechanism 

Displacement processes/scenarios 

Frequency/intensitiy 

Hazard assessment 

Levels of hazard (risk) 

Classification of intensity 

Intensity criteria: e.g. pressure 

Process-/Suszeptibility maps 

Hazard (information) maps 

Hazard zone maps 

The analysis of hazards is subdivided into several 

tasks: the survey and localization of hazard 

sources, the identification of triggering factors, 

the description of the triggering and displacement 

process and the potential effects (impact) on 

objects. The results of the hazard analysis are 

usually mapped in specific types of hazard maps 

(e.g. susceptibility maps, intensity maps). 

The analysis of natural hazards provides a 

comprehensive image of the processes, their causes 

and effects, but requires additional information 

concerning the order of magnitude of the relevant 

event. (RUDOLF-MIKLAU in BOLLSCHWEILER 

ET AL., 2011 [3.]) Consequently, the valuation of 

hazards aims at the description of magnitude in a 

graded manner. Hazards scales, physical intensity 

criteria or intensity classifications count among 

the established methods to present the magnitude 

of events. Usually the intensity of a hazardous 

process is functionally related to the frequency 

of its occurrence. In practice this “frequencyintensity-concept” 

is the preferentially applied 

RISKS 

Risk analysis 

Analysis of damages: direct/indirect damage 

Damage potential 

Damage scenarios 

Risk assessment 

Validation of risks 

Risk acceptance (aversion) 

Risk map 

Cartographical presentation of risks 

Risk management 

Definition of protection goals 

Creation of protection concepts 

Management plans 

Protection measures 

Effectiveness / Efficiancy 

Fig. 2: System of 

hazard and risk 

management 

(RUDOLF- 

MIKLAU/SAU- 

ERMOSER, 2011 

[16.]). 

Abb. 2: System 

des Gefahrenund 

Risikomanagements 

(RU- 

DOLF-MIKLAU/ 

SAUERMOSER, 

2011 [16.]). 

method for most natural hazards in order to value 

their effects (see below). (HÜBL, 2010 [8.]) 

Natural hazards in the Alpine 

environment are a complex system consisting 

of process chains with multiple interactions 

and dependencies. Thus the assessment of a 

hazard is not a mono-causal procedure but 

must take into account a large variety of more 

or less probable courses. (RUDOLF-MIKLAU 

in BOLLSCHWEILER ET AL., 2011 [3.]) The 

“scenario analysis” was established in risk 

management as an appropriate method to 

solve the complexity of comprehensive hazard 

assessment. Scenarios implicate that not only a 

single process but all relevant developments of 

an event within a defined period of recurrence 

are taken into account. (MAZZORANA ET AL., 

2009 [12.]) In practice this means: 

• Several assessment methods (e.g. 

morphologic, historic, stochastic) are 

applied. 

• Models have to be calibrated with 

regionally measurements and data from 

documented events ahead of application. 

• The application of physical models is not 

only performed for one single data set but 

for a frequency range of the input values. 

• Scenarios are checked concerning their 

plausibility. 

Approaches to hazard assessment: The “frequencymagnitude-concept” 

for design events (DE) 

According to ONR 24800:2008 [13.] an event 

represents the entirety of all processes occurring 

in a temporal, areal and causal relationship and 

corresponds to a specific probability of recurrence 

and intensity. The extreme event represents the 

maximum magnitude observed in the concerning 

catchment or risk area. The design event (DE) 

is applied as reference value (criteria) for the 

planning of protection measures and hazard 

maps and represents the striven level of safety 

(acceptable risk). (RUDOLF-MIKLAU, 2009 [14.]) 

The underlying concept of intensity and 

frequency was originally established by WOLMAN 

& MILLER (1960) [19.]. Intensity in colloquial use 

refers to strength or magnitude of a process or 

event. Intensity of natural events (hazards) can be 

expressed by physical criteria like discharge, flow 

depth, pressure (process energy) or area (mass) 

of deposited debris. (GEBÄUDEVERSICHERUNG 

GRAUBÜNDEN, 2004 [7.]) In general the 

frequency represents the period of recurrence 

between two events with comparable magnitude. 

Frequency is often expressed as return period, 

which is equal to the reciprocal of the exceedance 

probability of extreme precipitation or discharge 

values. As a rule the DE is determined according 

to a defined return period (e.g. flood with return 

period of 100 years). Frequency and intensity are 

functionally correlated. (RUDOLF-MIKLAU in 

BOLLSCHWEILER ET AL., 2011 [3.]) 

The frequency-intensity-concept is based 

on extreme value statistics and is appropriate for 

answering two basic questions: 

• How often does an extreme event of 

defined intensity occur statistically? 

• What is the expected extreme value for a 

defined time period? 

The two established methods to analyse extreme 

events are the “block-maxima-method” and 

the “peak-over-threshold-method” (KLEEMAYR 

in RUDOLF-MIKLAU & SAUERMOSER, 2011 

[16.]). For the statistic analysis, random and 

representative samples (data sets) are needed 

(e.g. time series of extreme precipitation). By 

means of statistical methods, it is attempted to 

conclude from properties of the sample to the 

rules of the “total population”. In technical terms, 

an unknown stochastic distribution function (e.g. 

Gumbel, Fréchet, Weibull) is derived from an 

empirical distribution of measured values. The 

most common field of application of the extreme 

value statistics is the prediction of weather 

extremes, extreme discharge in rivers and torrents 

of the extreme run-out distance of falls, slides or 

falls (mass movements or avalanches). The key 

problem of the method is the limited availability of 

measurements (data sets) that cover a sufficiently 

long period of time. In most cases the available 

data represents 

• either a too short observation (measuring) 

period, 

• or is fragmentary 

or both. Besides this major disadvantage, the 

method of extreme value statistics shows other 

considerable short comings. 

Especially for torrential processes, the frequencyintensity-function 

shows an “emergent” behavior 

implying a limited predictability of discharge 

from extrapolations of measurement data when 

a certain threshold value is exceeded. The event 

disposition of a catchment or risk area, defined


Seite 18 

Seite 19 

as the entirety of all conditions essential for the 

emergence of hazardous processes, consists of the 

basic disposition (susceptibility) comprising all 

factors immutable over a long range of time (e.g. 

geology, soils) and the variable disposition, which 

is the sum of all factors subject to a short-term or 

seasonal change (e.g. precipitation, saturation of 

soil with water, land use). If the variable disposition 

of a catchment or risk area is altered in the course 

of an event (e.g. exceedance of the water storage 

capacity of soil), the debris potential increases 

erratically, resulting in a possible transition of the 

predominant displacement process and a nonlinear 

increase of discharge. (HÜBL, 2010 [8.]) 

The practical procedure of specification 

of a design event can be lucidly explained by the 

example of a “design flood” (RUDOLF-MIKLAU & 

SEREINIG, 2010 [15.]): Generally, a design flood 

[discharge in m³/s] with a return period of 100 

years represents the striven level of safety for flood 

(torrent) control measures in European countries. 

Expected values for a rainfall and flood events of a 

defined return period (including a corresponding 

confidence interval) can be derived from the 

hydraulic extreme value statistics. Flood statistics 

are based on the assumption that the observation 

period is representative for the long-term runoff 

behavior of the watershed. However, extreme 

flood events are qualified as “statistical outliers” 

that are not represented by the measured data 

collection (due to limited observation periods), 

but nevertheless contribute valuable information 

on hydrological extremes. Consequently, the 

statistically deduced design criterion should be 

supported by additional information of temporal, 

spatial or causal reference. Especially the dating 

of historic flood events from chronicles or traces 

in nature (flood marks, “silent witnesses”) can 

provide precious additional information on 

return periods, levels of flooding, or peak flood 

discharge. By dating historic events, extreme 

floods can approximately be related to a certain 

return period. A causal supplement of information 

is gained if observed floods are analyzed with 

respect to their emergence regarding the weather 

conditions, the behavior of precipitation, and the 

disposition of the catchment area. 

In a first step, the determination procedure 

of the design flood requires the specification of 

the expected value of discharge by means of flood 

statistics and additional hydrological methods. 

From this basic design discharge, the design 

flood can be derived by taking into account solid 

transport, transient flow conditions and influences 

of stream morphology. 

The applicability of the frequencyintensity-concept 

is strongly limited for all types of 

hazards for which measurements or observation 

data of extreme events are insufficiently or 

generally not available. In addition, it has to be 

taken into account that the period of recurrence of 

a triggering event can significantly differ from the 

frequency of the impact (damage) event. Recently, 

alternative concepts for the assessment of 

magnitude of events are sought that could replace 

the “frequency-intensity-concept”. This holds 

especially true for the assessment of extreme mass 

movements and avalanches where frequency 

hardly can be determined with sufficient accuracy. 

Methods of hazard assessment 

The aim of hazard assessment is the determination 

of relevant scenarios and the related return period 

for the purpose of providing a prognosis of the 

substantial process, the extension and intensity of 

an event as well as for the magnitude of hazard 

(BRÜNDL ET AL., 2009 [5.]). 

Normally neither the physical properties 

of hazard processes are completely clarified, nor 

is sufficient data on extreme events available. 

Consequently, the most important principle of 

hazard assessment is the compliance of a high 

redundancy in the procedures and methods applied 

(KIENHOLZ, 2005 [10.]). Two principle approaches 

are eligible for hazard assessment (Fig. 3): 

• The analysis of past events (retrospective 

indication). 

• The prognosis of future events (foresighted 

indication). 

Morphological Method: This method 

is based on the identification of triggering/ 

displacement processes and the spatial distribution 

by means of “silent witnesses” (AULITZKY, 1992 

[1.]) in the morphology (deposition area) and at 

the vegetation (e.g. trees). Dendromorphology 

counts among these methods, which (besides 

other dating methods (BOLLSCHWEILER ET. AL., 

2011 [3.])) provides 

Historical Method 

Retrospective Indication comprehensive time 

chronicles, witnesses 

series of past events. 

Statistical Method: 

is based on the assumption, that an occured event 

will reoccur with comparable course and effects. 

Morphological Method 

This method includes 

„silent witnesses“, dendromophology 

the analysis of 

measurements 

Statistical Method 

and observation 

extreme value statistics, triggering Foresightes Indication 

(monitoring) data by 

mechanism 

means of stochastic 

is based on the identification and analysis of factors 

Physical/Mathematical 

methods (e.g. extreme 

and processes, which represent evidence for 

Method 

existing hazards according to gained experiences. value statistics). 

Numerical/empirical models 

The method presupposes knowledge about the Nevertheless, the 

triggering mechanism, the displacement process derivation of reliable 

and the effect (impact) and includes the 

Pragmatic Method 

investigation of probability of recurrence 

(significant) trends 

Expert opinion (estimation) 

(return period). 

and prognoses 

requires a sufficient 

Fig. 3: Principle approaches to hazard assessment (after KIENHOLZ, 2005 [10.]; modified). 

quantity of data for 

Abb. 3: Grundlegende Vorgehensweisen bei der Gefährdungsanalyse 

a representative 

(nach KIENHOLZ, 2005 [10.]; geändert). 

time (observation) 

According to these principles, the following 

procedures can be chosen and should be 

applied corresponding to the rule of redundancy 

(HÜBL et al., 2007 [9.]): 

Historical Method: The method is based 

on the (qualitative and quantitative) analysis of 

reports, testimonies and chronicles of past events 

(catastrophes). This data provides evidences 

for the frequency of events, the triggering 

mechanism and the extension of the process as 

well as the damages occurred. As a rule, historic 

sources tend to be fragmentary and distorted due 

to subjective perception. 

period. (KLEEMAYR in RUDOLF-MIKLAU & 

SAUERMOSER, 2011 [16.]) 

Physical/Mathematical Method: These 

methods are mainly based on numerical or 

empirical models, which provide information 

(physical criteria) for the intensity of an event 

for a defined return period. In practice models 

are the preferred tool for the determination of 

design events in natural hazard engineering. Due 

to the limited accuracy of numerical models, the 

application always presupposes a calibration of 

regional measurements (data) and the validation 

of the results with expert opinions. In addition,


Seite 20 

Seite 21 

models should not only be applied for a single 

data set but for a range of scenarios as well as for a 

distribution of input parameters. A comprehensive 

summary of available models for torrential 

processes is given in BERGMEISTER ET AL. (2009) 

[2.], for avalanches in RUDOLF-MIKLAU & 

SAUERMOSER (2011) [16.]. 

Pragmatic Method: This method is 

based on the “expert opinion” of experiences 

practitioners and local experts. The pragmatic 

method is applied if other methods are not 

applicable or do not meet the goal of satisfying 

hazard (risk) assessment. In addition, this 

method serves as a redundancy and is used for 

the validation of results of “exact” assessment 

methods (mentioned above). 

Hazard assessment methods always 

suffer from major restrictions concerning their 

meaningfulness and accuracy. For the interpretation 

and validation of results, it is essential to know 

the sources of uncertainties and methodical 

short-comings. Some of these deficiencies are 

summarized below (KIENHOLZ, 2005 [10.]): 

• Limited availability of data 

• Limited observation (measuring) period 

• Lack of “direct” measurements (e.g. 

velocity of mass propagation during events; 

impact pressure) 

• Incomplete or false documentation of past 

events 

• Inconsistent quality of information and data 

due to variable measuring (observation, 

monitoring, documentation) standards 

• Uncertainties in the selection of relevant 

scenarios 

• Misjudgement of the effeminacy and 

condition (usability) of existing protection 

measures 

• Misjudgement concerning the “residual risk” 

Preventive planning: principles and function 

“Prevention by planning” today is qualified as 

the most effective measure in natural hazard 

management. Planning in relation to natural 

hazards and risks can also unfold active as 

passive protection effects. Planning procedures 

concerning natural hazards are not limited to the 

cartographic outline of endangered areas (areas 

at risk), but also provide the passivity to reduce 

hazards/risk by keeping endangered areas free 

from buildings or limiting the use of these zones 

(e.g. inundation areas). Thus preventive planning 

is the basis for the protection strategy “prevention 

by area”. (RUDOLF-MIKLAU, 2009 [14.]) 

In addition, the cartographic depiction of 

hazard zones provides the essential information 

(process intensity, magnitude of impact forces) 

for the technical protection of existing buildings. 

Also the suitability of planned building sites 

concerning the risk by natural hazards can be 

efficiently judged on the basis of hazard maps. 

In development planning, the localization of new 

settlements can be steered away from impending 

hazards. (BUWAL/BRP/BWW, 1997 [6.]) 

In principle, in the Alpine environment 

the usability of land for building purposes is 

limited according to the expansion of hazards. 

In mountainous regions, the total avoidance 

of hazard zones for spatial development is not 

possible. Consequently, preventive planning 

defines limits (border lines) for areas that are 

appropriate for building. Within these limits, 

hazard maps provide bases for standards and 

regulations for a hazard-adapted construction 

practice. 

Logically, the main emphasis of preventive 

planning lies in the sector of hazards spatially 

“delimited” in action, such as floods, avalanches, 

mass movements. For natural hazards that do not 

allow an “exact” delimitation (e.g. earthquake, 

storm, forest fire, snow load), preventive planning 

is limited to rough-scale maps showing a general 

gradation of risks. (RUDOLF-MIKLAU, 2009 [14.]) 

The environmental planning is of major 

importance for the application of hazard maps. 

Consequently, preventive planning can be 

understood as a part of development planning. 

In order to regulate the use and development of 

endangered areas, the intervention of the state 

is essential. The primary goal of development 

planning concerning natural hazards is to keep 

the endangered areas free from buildings (passive 

protection function). The active protection function 

of preventive planning lies in the reservation 

(provision) of areas for the spreading of hazardous 

processes (e.g. inundation areas) or in the provision 

of standards (limits) for the use of endangered areas 

in order to reduce the risk potential. 

Mapping hazards in Alpine environment 

The cartographic outline of endangered areas 

according to KIENHOLZ (2005) [10.] includes the 

elaboration of scientific and technical bases and 

the depiction in hazard (indication) maps. In a 

second step, the geographic information provided 

on triggering disposition and impact intensity of 

hazardous processes is used for the provision 

of hazard zone maps and their implementation 

in the process of development planning. As a 

rule, hazard maps have no legal liability but are 

defined as “spatial expert opinions with prognosis 

character”, while the hazard zones become 

legally binding only by incorporating them into 

development planning documents (land use 

maps). Thus legal liability of hazard zones may 

arise on the local level depending on the national 

legal framework. 

Consequently, it is essential to adapt the 

standards of hazard mapping to the requirements 

and goal of development planning on the regional 

and local level. In the Alpine countries in general 

the following categories of maps for the outline of 

hazards and risks can be distinguished: 

• Process maps (susceptibility, intensity) 

• Hazard (indication) maps 

• Hazard zone maps 

• Risk maps 

The following definitions are valid only with 

restrictions since terminology of hazard mapping 

substantially differs between countries and 

scientific branches. 

A hazard (indication) map roughly 

indicates in which areas natural hazard have to be 

taken into account in land use and development 

activities. The character of the map is only 

demonstrative, while no concrete information 

about the magnitude of the danger is provided. 

In many countries hazard zone maps are not 

available, leaving hazard indication maps as the 

only source of spatial information. 

Process maps show hazards by the 

spatial distribution of physical parameters 

(criteria) describing the triggering, displacement 

and impact processes. These maps are most often 

the result of numerical or empirical modeling. In 

some countries, process maps are transformed 

into intensity maps showing the process criteria 

graded according to the levels of impact intensity 

(e.g. Switzerland: frequency-intensity-matrix; 

LOAT, 2005 [11.]). Susceptibility is defined as the 

extent to which an area suffers from the risk of 

emergence of a hazardous process if exposed to a 

triggering factor, without regard to the likelihood 

of exposure. Analogously, susceptibility maps 

show the disposition of an area for these events, 

but does not provide information about the 

frequency and expected intensity. 

Hazard zone maps show the impact of 

processes according to its magnitude (intensity, 

frequency) on the scale of the local cadastre 

(1.2000 – 1.5000). Consequently, these


Seite 22 

Seite 23 

Fig. 4: Hazard indication map for mass movements (Bavaria, 

Germany). 

Abb. 4: Gefahrenhinweiskarte für Massenbewegungen 

(Bayern, Deutschland). 

maps provide specific information about the 

usability of certain plots for building or other 

development purposes. Hazard zone maps are 

regularly produced for the hazard types floods, 

avalanches and debris flow, and only in few 

countries (Switzerland, France, and Italy) for 

mass movements as well. In most countries, 

hazard zone maps are regulated by legal and 

technical standards concerning their content, 

formal requirements, approval procedure and 

implementation in the development planning. 

Some countries have also defined a specific design 

Fig. 5: Hazard map for falls (rock fall) (Switzerland). 

Abb. 5: Gefahrenzonenplan Felssturz (Steinschlag) (Schweiz). 

Fig. 6: Hazard zone map for torrents (including indication of 

landslide areas) (Austria). 

Abb. 5: Gefahrenzonenplan Wildbäche (einschließlich des 

Hinweises von Rutschgebieten) (Österreich). 

event (period of recurrence) for the assessment of 

the relevant hazards. (HÜBL ET AL., 2007 [9.]) 

The elaboration of risk maps is based on the 

depiction of objects at risk (risk potentials) within 

endangered areas. In principle there are two types 

of risk maps available (BORTER ET AL., 1999 [4.]): 

• Risk maps only showing risk potential 

without assessing (value) them. 

• Risk maps based on a graded, qualitative 

or quantitative assessment of risks (levels 

of risk; e.g. low – medium - high). These 

maps are elaborated by combining the 

impact intensity with the damage potential 

(value), the vulnerability and the exposition 

of objects/persons in the endangered area. 

Closing remarks 

Hazard (risk) assessment and mapping count 

among the most important tasks (measures) in 

natural hazard management. The maps provide 

the key information for most of the other mitigation 

measures in order to reduce risk to an acceptable 

level. GIS technology provides a powerful tool to 

combine spatial information on natural hazards 

with other cartographic information concerning 

human activities and development actions. 

Overlaying this information makes feasible a 

comprehensive assessment of risks for human 

health, economic acidities, environment and 

cultural heritage. 

As shown in this article, the methods 

for the assessment of natural hazards still suffer 

from major short-comings and significant sources 

of inaccuracy. In addition, a comprehensive 

understanding of the triggering and displacement 

processes of Alpine natural hazards is still 

missing due to the limited availability of “direct” 

measurements and observation. 

Although hazard maps have gained a 

key role in the process of preventive planning, 

the information provided by these maps should 

still be treated with care and only be interpreted 

by experts. This reservation especially holds true 

for hazard maps devoted to mass movements. 

As the standards of hazard mapping in this field 

are still under development, preventive planning 

concerning rock fall and landslides (unlike flood 

and avalanche hazards) is still “in situ nascendi”. 

This delay justifies the strong efforts within the 

Alpine space to establish and harmonize general 

standards for the assessment and mapping of 

hazards caused by mass movements. 

Anschrift des Verfassers / Author’s address: 

DI Dr. Florian Rudolf-Miklau 


Umwelt und Wasserwirtschaft, Abteilung IV/5, 

Wildbach- und Lawinenverbauung 


Enviroment and Water Management, Department 

IV/5, Torrent and Avalanche Control 


Tel.: (+43 1) 71 100 - 7333 

FAX: (+43 1) 71 100- 7399 

Mail: florian.rudolf-miklau@lebensministerium.at 



[1.] AULITZKY H. (1992): 

Die Sprache der "Stummen Zeugen". Tagungsband der Internationalen 

Konferenz Interpraevent 1992, S. 139-174. 

[2.] BERGMEISTER K., SUDA J., HÜBL J., RUDOLF-MIKLAU F. (2009): 

Schutzbauwerke der Wildbachverbauung. Verlag Ernst und Sohn Berlin 

(Wiley VCH). 

[3.] BOLLSCHWEILER M., STOFFEL M., RUDOLF-MIKLAU F. (2011): 

Tracking torrential processes on fans and cones. Springer Dortrecht (in 

preparation). 

[4.] BORTER P. (1999): 

Risikoanalyse bei gravitativen Naturgefahren. Bern: Bundesamt für 

Umwelt, Wald und Landschaft BUWAL. Umwelt-Materialien 107/I+II. 

[5.] BRÜNDL M., ROMANG H., HOLTHAUSEN N., MERZ H., BISCHOF 

N. (2009): 

Risikokonzept für Naturgefahren – Leitfaden; Teil A: Allgemeine 

Darstellung des Risikokonzepts. Bern: Nationale Plattform Naturgefahren 

PLANAT (vorläufige Fassung). 

[6.] BUNDESAMT FÜR UMWELT, WALD UND LANDSCHAFT 

BUWAL, BUNDESAMT FÜR RAUMPLANUNG BRP, BUNDESAMT FÜR 

WASSERWIRTSCHAFT BWW (1997): 

Berücksichtigung von Hochwassergefahren bei der raumwirksamen 

Tätigkeit, Biel. 

[7.] GEBÄUDEVERSICHERUNG GRAUBÜNDEN (2004): 

Vorschriften für bauliche Maßnahmen an Bauten in der blauen Lawinenzone. 

[8.] HÜBL J. (2010): 

Hochwässer in Wildbacheinzugsgebieten. Wiener Mitteilungen (in press). 

[9.] HÜBL J., FUCHS S., AGNER P. (2007): 

Optimierung der Gefahrenzonenplanung. Weiterentwicklung der 

Methoden der Gefahrenzonenplanung. IAN-Report 90. Wien: Universität 

für Bodenkultur (unveröffentlicht). 

[10.] KIENHOLZ H. (2005): 

Gefahrenzonenplanung im Alpenraum – Ansprüche und Grenzen, Imst: 

Imst: Wildbach- und Lawinenverbau (Zeitschrift für Wildbach-, Erosionsund 

Steinschlagschutz), Nr. 152, 135-151. 

[11.] LOAT R. (2005): 

Die Gefahrenzonenplanung in der Schweiz. Imst: Wildbach- und 

Lawinenverbau (Zeitschrift für Wildbach-, Erosions- und Steinschlagschutz), 

Nr. 152, 77-92. 

[12.] MAZZORANA B., FUCHS S., HÜBL J. (2009): 

Improving risk assessment by defining consistent and reliable system 

scenarios, Nat. Hazards Earth Syst. Sci., 9: 145–159. 

[13.] ONR 24800: 

2008, Schutzbauwerke der Wildbachverbauung – Begriffe und ihre 

Definition sowie Klassifizierung. Austrian Standards Institute, Vienna. 

[14.] RUDOLF-MIKLAU F. (2009): 

Naturgefahren-Management in Österreich. Verlag Lexis-Nexis Orac . 

[15.] RUDOLF-MIKLAU F., SEREINIG N. (2009): 

Festlegung des Bemessungshochwassers: Prozessorientierte 

Harmonisierung für Flüsse und Wildbäche, ÖWAW 7-8: 29 – 32. 

[16.] RUDOLF-MIKLAU F., SAUERMOSER S. (Hrsg.) (2011): 

Technischer Lawinenschutz. Verlag Ernst und Sohn/Wiley Berlin (in 

preparation). 

[17.] SCHROTT L., GLADE T. (2008): 

Frequenz und Magnitude natürlicher Prozesse; in Flegentreff, Glade (Eds.): 

Naturrisiken und Sozialkatastrophen. Spektrum Akademischer Verlag 

Springer: 134 – 150. 

[18.] SUDA J., RUDOLF-MIKLAU F., HÜBL J., KANONIER A. (Hrsg.) (2011): 

Gebäudeschutz vor Naturgefahren. Verlag Spring Wien (in preparation). 

[19.] WOLMAN M. G., MILLER J. P. (1960): 

Magnitude and frequency of forces on geomorphic processes. Journal of 

Geology 68 (1): 54 – 74.


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Seite 25 

RICHARD BÄK, HUGO RAETZO, KARL MAYER, 

ANDREAS VON POSCHINGER, GERLINDE POSCH-TRÖZMÜLLER 

Mapping of Geological Hazards: Methods, Standards 

and Procedures (State of Development) - Overview 

Geologische Gefahrenkartierung: Methoden, Standards 

und Verfahren (derzeitiger Status) – ein Überblick 


Die geologische Gefahrenkartierung ist in Europa trotz unterschiedlicher Methoden eine 

anerkannte Notwendigkeit für die Prävention. Die wissenschaftliche Charakterisierung der 

Massenbewegungen basiert oft auf ähnlichen Methoden und ist deshalb eher vergleichbar. 

Hingegen ist die Umsetzung in die Raumplanung und in das Risikomanagement auf europäischer 

Ebene sehr unterschiedlich. Der Grund liegt primär in unterschiedlichen Gesetzen, 

Verordnungen und Verantwortlichkeiten, bzw. in sozio-ökonomischen Eigenheiten 

der Länder. Während in Italien und in der Schweiz technische Richtlinien bzw. gesetzliche 

Regelungen zur Erstellung von Gefahrenkarten bestehen, gibt es in Österreich nur für 

Hochwasser bzw. Lawinen Regelungen zur Ausweisung von Gefahrenzonen. In Deutschland 

wurde eine Empfehlung für die Erstellung von Gefahrenhinweiskarten publiziert. Aufgrund 

fehlender Regelungen in den alpinen Staaten Europas werden Ereigniskarten, Indexkarten, 

Gefahrenhinweiskarten und Gefahrenkarten als Grundlagen für die Gefahrenbeurteilung in 

verschiedenen Maßstäben mit unterschiedlichem Inhalt erarbeitet. Dies und unterschiedliche 

Definitionen erschweren den Vergleich. Ein multilinguales Glossar, die Einrichtung 

von Ereigniskatastern bei der Verwaltung und die Festlegung von Mindestanforderungen zur 

Erstellung von Grundlagen und Gefahrenkarten (Anforderungen hinsichtlich Eingangsdaten 

und Zweck) sollten daher ein primäres Ziel sein. Im Projekt AdaptAlp (Interreg IV B, Alpine 

Space) arbeiten die Alpenländer an gemeinsamen Grundsätzen. 

Summary: 

In spite of different methods used, geological hazard mapping is accepted as a tool for 

hazard prevention in Europe. Scientific characterization of mass movements is based on 

similar methods with mostly comparable results. However, the implementation in spatial 

planning and risk management differs considerably due to different regional legal acts, 

ordinances, responsibilities and pecularities. Whereas in Italy and Switzerland there are 

technical guidelines and legal acts regarding landslides and rock fall, in Austria only hazard 

mapping concerning floods and avalanches is regulated. In Germany a recommendation 

on how to create a susceptibility map was published. Because of a lack of regulations in 

European Alpine states’ inventory maps, susceptibility and hazard maps are created in 

different scales with different contents and quality. This, as well as different defintions of 

terms such as susceptibility, danger and hazard, makes comparison of hazard assessment 

products difficult. Consequently a multilingual glossary, landslide inventories at regional 

authorities and minimal requirements as to how to create hazard maps (requirements 

concerning input data and purpose of assessment) are necessary. In the AdaptAlp project 

(Interreg IV B, Alpine Space) the Alpine regions elaborate the common principles. 

Introduction 

In Alpine regions, slopes of different 

morphological and geological conditions are 

prone to landslides. Taking into consideration 

one of the geological principles for landslide 

hazard assessment – the past is the key to the 

future – future slope failures will probably occur 

in areas with similar geological, morphological 

and hydrological situations that have led to past 

failures. Some triggering mechanisms happen 

sporadically and are not readily obvious. Because 

of the lack of memories of past landslide events, 

the susceptibility to mass movements is not 

considered accurate in land use. But the effects 

of mass movements (damages) necessitate new 

strategies on how to manage the future potential 

of natural (geological) hazards in alpine regions. 

Information about landslides in alpine 

countries varies in its quality and quantity: In 

some regions, detailed landslide inventories exist 

and are the basis for susceptibility and hazard 

assessment. Different approaches to hazard 

mapping are in practice. This fact and dissimilar 

meanings for terms like susceptibility, danger 

and hazard make a comparison of the regional 

approaches difficult. Using various input data also 

handicaps the comparison of hazard assessment. 

Within the INTERREG IV B project 

“Adaptation to Climate Change in the Alpine 

Space “ (acronym AdaptAlp), work package 

5.1 Hazard Mapping - Geological Hazards is 

focusing on the transnational harmonization of 

standards (minimal requirements in the field of 

hazard assessment and mapping) by exchanging 

experiences in the partner regions. This issue 

provides an overview of methods, standards and 

procedures without a pretense of completeness. 

The definitions of terms used regarding


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landslides sometimes differ contradictorily in 

literature and in practice. For this reason the 

second goal of the work package 5.1 named 

above is the elaboration of a multilingual glossary. 

Landslide inventories 

Landslide inventories are the basis for all scientific 

and planning activities. They contain the basic 

data of natural hazard processes and should 

mainly include the facts. Therefore all partner 

countries in the AdaptAlp Interreg project are 

working on landslide inventories. 

[11] Guzzetti 2005 wrote about landslide 

inventories: “Despite the ease with which they 

are prepared and their immediateness, landslide 

inventories are not yet very common. Inventory 

maps are available for only a few countries 

and mostly for limited areas. This is surprising 

because inventory maps provide fundamental 

information on the location and size of landslides 

that is necessary in the assessment of slope 

stability at any scale, and in any physiographical 

environment.” Nevertheless, all of the countries 

considered for the literature survey have landslide 

inventories and maps, even if contents, scales and 

the state of completeness vary. 

In order to predict landslide hazard 

in an area, the morphological, geological, and 

hydrological conditions and processes have to be 

identified. Their influence on the stability of the 

slopes has to be estimated. 

Different methods of data acquirement 

are used to establish databases to assess hazards: 

Landslide inventories as an important tool for the 

assessment of the susceptibility of slopes to mass 

movements are created nowadays more and more 

using digital technology. A general indication of 

landslide susceptibility can be obtained based on 

landslide inventories, geological, soil and geomor- 

phological maps. Using digital DTM data in a GIS 

allows the production of hillshades with several 

geometries to detect typical landslide forms. 

Modern methods for modelling processes are designed 

for the GIS environment. Slope stability and 

rock fall trajectories can be computed over large 

areas to get indications of the hazards. Analysis 

of aerial photographs is also a classical and 

valuable technique to identify landslide features. 

More subtle signs of slope movement cannot be 

identified on the maps mentioned above. Field 

observation by experts is necessary for accurate 

assessment. The requirements for acquired data 

are raised by the main goal: The accurateness and 

detail of input data and scale depends on the aim 

of the product – susceptibility map, hazard assessment 

or risk analyses. 

For hazard assessment, information 

about possible scenarios is needed. For this 

reason it is important that landslide inventories 

are induced to sustain landslide knowledge over 

time. In most regions of the Alps, inventories have 

been established by authorities and are to some 

extent available to the public. 

Tab.1 gives information about what 

kind of data is stored in different landslide event 

inventories, and what questions are asked on the 

landslide reporting form. For the comparison, 

information from the countries Austria (Geological 

survey of Austria, of Lower Austria, of Carinthia, 

project MASSMOVE, project DIS-ALP), Germany, 

Switzerland, Slovenia, Italy, France, Slovakia, Australia 

and the USA (Oregon, Washington, Utah) 

was taken into account. 

The first section of table 1 shows 

if inventories exist. The second section 

deals with the basic data, mainly with the 

5W-questions: What happened where, when and 

why, and who reported it (or made the database 

entry). The landslide conditions in the third section 

give evidence, if e.g. information on the activity, 

geometry and slope position of a landslide is 

recorded. Recorded geological information 

(fourth section) is sometimes specified in detail, 

sometimes only the information is given that 

geological information is being stored. 

In many cases additional information 

such as data on vegetation (land cover), 

hydrogeological or hydrological conditions, as 

well as specific data such as the shadow angle are 

stored in the databases. 

Most inventories provide information on 

the causes or triggers of landslides. In some cases 

the damages due to landslides are listed in the 

inventory, sometimes even the monetary value of 

the damage and the costs of remediation measures. 

Most inventory forms also provide information 

about how the listed data was gathered (e.g. field 

survey), some provide a rating about the reliability 

of the degree of precision of the information. In 

most databases additional reports, documentation 

and bibliography are included or mentioned. 

In Austria the Geological survey of 

Austria, in cooperation with the Geological Survey 

of Carinthia, has created not just one “inventory 

map” but a “level of information” (Fig. 1): 

Process index maps (map of phenomena 

“Prozesshinweiskarte”, “Karte der Phänomene”) 

can have different scales (1:50,000 and bigger) 

and can be of varying quality; it contains 

information about process areas and phenomena 

of mass movements that have already happened. 

The event inventory (“Ereigniskataster”) records 

only those processes for which an event date is 

known (5W-questions); it is independent of a 

scale. In Carinthia, a digital landslide inventory 

was created with historical events of the last 

50 years ([7] Bäk et al. 2005). The inventory 

map/event map (“Ereigniskarte”) contains only 

information about processes for which an event 

date is known. The thematic inventory map 

contains only information related to a type of 

process, categorized according to the quality of 

the data. 

In Switzerland, the generation of a “map 

of phenomena” is mandatory ([30] Raetzo 2002). 

As with the Austrian “map of phenomena”, it 

shows the geologic-geomorphologic features. An 

extensive manual with a digital GIS-legend was 

published on a DVD by BWG ([8]BWG 2002, 

[14] Kienholz & Krummenacher 1995). 

The scale used depends on the purpose 

the map is used for, ranging from 1:2,000 (or 

even more) for a detailed study to 1:50,000 as 

an indicative map ([32] Raetzo & Loup 2009). 

On the other hand, the Federal Office for the 

Environment (FOEN) manages a database with 

all the events where damages were recorded. This 

national database is called “StorMe” and contains 

data on every natural hazard process: landslides, 

debris flows, snow avalanches and floods. 

In Italy, a country with a particularly high 

landslide risk owing to its landform configuration 

and its lithological and structural characteristics, 

the need for a complete and homogeneous 

overview of the distribution of landslides was 

recognized after the disastrous event at Sarno. The 

aim of the IFFI Project (Inventario dei Fenomeni 

Franosi in Italia – “Italian Landslide Inventory”) 

implemented by ISPRA (formerly: APAT, the 

Italian Environment Protection and Technical 

Services Agency) and by the regions and selfgoverning 

provinces was to identify and map 

the landslides in accordance with standardized 

and shared methods. The work method included 

the collection of historical and archive data, 

aerial photo interpretation, field surveys, and 

detailed mapping. A “Landslide Data Sheet” was 

prepared for collecting the landslide information, 

subdivided into three levels of progressively


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increasing detail (from: [13] ISPRA, 2008): 

• First level: contains the basic information 

(location, type of movement, state of 

activity) and is mandatory for every 

landslide. 

• Second level: contains the geometrical, 

geological, and lithological parameters, 

land use, causes and activation date. 

• Third level: provides detailed information 

on the damage, investigations and remedial 

measures. 

A scale of 1:10,000 is used for surveying and 

mapping the landslides throughout most of Italy, 

only in high mountainous areas or in lower 

populated areas is a scale of 1:25,000 used. As 

with many regions, the region of South Tyrol 

(Autonome Provinz Bozen Südtirol, [27] Nössing 

2009) also has a landslide database that resulted 

from the IFFI Project. The type of movement, the 

litho-logical unit, the volume of the moving masses, 

the internal cause and the external trigger, as well 

as the induced damage are noted for each event. 

The extensive landslide database, 

GEORISK of Bavaria, is an essential step to 

creating susceptibility maps. Until now 2,800 

landslides have been documented in the 

database, with information about the type of 

movement, the extension, age and status of the 

landslides. The following landslide processes are 

recorded: flow ("Hangkriechen", "Schuttströme"), 

slide ("Rutschungen", "Hanganbrüche"), fall/rock 

fall ("Steinschläge", "Felsstürze", "Bergstürze"), 

Karst, subsidence ("Erdfälle", "Dolinen", "Senken", 

"Schwinden",..). Based on the inventory, maps 

were created, showing existing landslides and 

their activity (“Karten der Aktivitätsbereiche”). 

The Slovenian landslide inventory map 

is shown as a small inlet on the susceptibility 

map of Slovenia at a scale of 1:250,000. Personal 

information from M. Komac (Geo ZS) revealed 

that, since the sources for the inventory map of 

Slovenia are quite different from each other, the 

scales vary but landslides were always mapped at 

a quite detailed scale. 

In France a database for mass movements 

is accessible on the internet. The processes taken 

into account are landslides, rock fall, debris flows, 

subsidence and bank erosion. For each mass 

movement, the following detailed information 

can be retrieved: type of movement, detailed 

geographical data, information about the quality, 

the precision and the origin of the data, detailed 

information about the mass movement (size, 

activity), the damage caused, the causes for the 

movement and geological information as well as 

information about the survey of the phenomenon. 

A prototype landslide database has 

been established by Geoscience Australia in 

collaboration with the University of Wollongong 

and Mineral Resources Tasmania, displaying the 

location of the landslides on a map and providing 

information regarding the type of landslide, date 

of occurrence (if known), a brief summary of the 

event, its cause and damage. 

In England after the Aberfan disaster the 

UK government funded a number of research 

projects to look at the UK’s geohazards ([33] 

Reeves 2010). Now in the UK the BGS investigates 

geohazards by looking at primary geohazards such 

as earthquakes, volcanic eruptions and secondary 

geohazards such as landslides, swelling/shrinking 

etc. Topics of consideration are the cause of 

events, return periods determined by analysis of 

past events, affected regions, influence of regional 

geology. An inventory is the first step in building an 

understanding of the occurrence of geohazards. 

Currently BGS maintains two main shallow 

geohazard databases: the National Landslide and 

the Karst Database. These inventories provide 

the basis for analysing the spatial distribution 

of the geohazards and their causal factors. This 

understanding can be used to assess susceptibility. 

In the USA the Landslide Inventory 

Steering Committee, composed of members of 

USGS and State Geological Surveys and other 

state agencies, are working on the Landslide 

Inventory Pilot Project. The purpose of this project 

is to provide a framework and tools for displaying 

and analyzing landslide inventory data collected 

in a spatially aware digital format from individual 

states. To get information about further landslides, 

the Oregon Department of Geology and Mineral 

Industries, among others, has prepared an 

inventory form. Besides information about the 

exact location (coordinates) of a landslide, the 

following specifications should be listed: date of 

slide, activity, estimated dimension (length, width, 

depth, volume, estimated dimensions from: aerial 

photos, field evaluation), predominant type of 

material (rock, debris, earth, fill), predominant 

type of movement (fall/topple, flow, translational 

slide, rotational slide, spread), approximate 

original slope (e.g.: 30° +/- 5°, estimated from 

e.g. 1:24K USGS topo map), land use where 

slide occurred (forested area, harvested area, 

rural area, urban area, agriculture), cause of slide 

(road construction, road cut, road fill, earthquake, 

preexisting slide, steep natural slope, natural 

drainage, human built drainage, other), damage 

caused by slide and additional comments. 

In California the landslide inventory 

maps are available at a scale of 1:24,000. 

The inventory was prepared primarily by 

geomorphological analysis, interpretation of aerial 

photographs and also by field reconnaissance, 

interpretation of topographic map contours, and 

review of geological and landslide mapping. 

Also, each landslide was classified according to 

its activity: active or historic, dormant-young, 

dormant-mature, dormant-old. The landslide 

material (rock, soil, earth, debris) and type of 

movement (slide, flow, fall, topple, spread) are 

also classified. Furthermore, each landslide is 

classified according to a “confidence” (definite, 

probable, questionable) assigned by the geological 

interpreter. It can be regarded as a measure of 

likelihood that the landslide actually exists. 

Susceptibility/hazard assessment in Alpine regions 

A literature study regarding susceptibility/hazard 

mapping ([29] Posch-Trözmüller 2010) shows 

the different approaches to hazard assessment in 

alpine regions. 

For the assessment of natural hazards 

(hazard maps) mainly heuristic methods are in 

practice. In this case scientific reports, geological 

and morphological mapping are the basis for 

weighting methods. Statistical analysis (bivariante 

or multivariate) are used for the weighting. The 

weight of evidence method is based on a statistical 

Bayesian bivariate approach. Originally developed 

for ore exploration, this probabilistic method is 

now commonly used for the statistical assessment 

of landslides. It is based on the assumption that 

future landslides would be triggered or influenced 

by the same or similar controlling factors as 

previously registered landslides ([15] Klingseisen 

& Leopold 2006, [16] Klingseisen et al. 2006). 

In Germany a recommendation on how 

to create a susceptibility map is given by the 

“Geohazards” team of engineering geologists 

of German federal governmental departments 

of geology ([37] SGD 2007). Basic minimal 

requirements for inventory records are defined, 

such as spatial positioning and technical data of 

mass movements. Digital modelling (rock fall, 

shallow landslides) can be used to identify the 

susceptibility of areas to mass movements, verified 

by landslide inventories or evaluation through


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field work. Indications of active/inactive landslides 

can be found by using registers, mapping and/or 

remote sensing (DTM) methods. Potential landslide 

areas (where landslides have not yet taken place) 

are determined by empirical methods in account 

of geological and morphological situation and 

land use. Alternatively areas prone to landsliding 

can be derived semi-automatically by a cross-over 

between DTM and a geological entity. Regarding 

rock fall processes, source areas of rock fall are 

derived in a first step from landslide inventories 

and/or remote sensing (DTM). Usually Alpine 

areas with an inclination > 45° are potential rock 

fall escarpments. In the second step, the runout 

zone is depicted by empiric angle methods 

(shadow angle, geometric slope angle) or physical 

deterministic methods. The guidelines also include 

flow processes, subrosion, subsidence and uplift. 

For the whole Bavarian Alps (about 

4.300 km²) ([23] Mayer 2007), an “extended 

danger map” at a scale of 1:25,000 has already 

been presented or is being completed. That 

means that, in contrast to the susceptibility map 

(without information on intensity and probability), 

it includes a qualitative statement about the 

probability through a predefined “design event”. 

The legend for the rock fall danger map discerns 

between “indication of danger”, yes or no, the 

legend for the danger map of superficial landslides 

discerns 3 entries (source area, accumulation 

zone, none), the deep-seated landslides danger 

map also discerns 3 entries (indication, indication 

in extreme case, none). 

The Swiss indicative map (“Gefahrenhinweiskarte”) 

is generated at a scale of 

1:10,000 to 1:50,000. The legend gives only the 

information “indication of hazard” - yes or no, 

without specification of classes. It indicates the 

potential process areas of rock falls, landslides 

and debris flows. It doesn’t include information 

about intensity or probability. The creation of an 

indicative map is not obligatory in Switzerland, 

since the law refers to the standardized hazard 

map ([32] Raetzo & Loup 2009). Detailed 

information on hazard maps in Switzerland is 

given by Raetzo & Loup in this issue [31]. 

Because of the lack of a regulatory 

framework or technical norm concerning 

landslides and rock fall in Austria - only the 

course of actions concerning floods, avalanches 

and debris flows are regulated by law (ordinance 

of hazard zone mapping, [34] Rudolf-Miklau & 

Schmidt 2004) - the federal states all follow a 

different course of action. 

At the Geological Survey of Austria, 

a database-system for documenting mass 

movements in Austria (GEORIOS) containing 

information about the different types of 

processes, geological, hydrological, geometric 

and geographical data, information on studies or 

tests carried out as well as mitigation measures 

and the source of information (archives, field 

work) is in use. Susceptibility maps in different 

scales and with different methods (heuristic 

approach, neural network analysis) have already 

been generated. Using the digital geological 

map (1:50,000), the inventory map, map of 

phenomena and a lithological map, susceptibility 

maps for Carinthia were generated in collaboration 

with the Geological Survey of Austria 

(GBA) and the Geological Survey of Carinthia at a 

scale of 1:200,000 ([17] Kociu et al., 2006). These 

are, of course, still lacking information about 

intensity and recurrence period or probability 

of occurrence. For a small study area in Styria, 

the Geological Survey of Austria generated a 

susceptibility map at a scale of 1:50,000 using 

neural network analysis ([38] Tilch 2009). 

In Vorarlberg risk maps (susceptibility 

map, vulnerability map, risk map) were produced 

in the course of a university dissertation ([35] 

Ruff 2005). For modelling, he used bivariate 

statistics (landslides) and cost analysis (rock falls), 

working with a 25x25m grid. The inventory map is 

included in the susceptibility map. Also, the local 

department of the Austrian Service for Torrent 

and Avalanche Control (WLV) creates “hazard 

maps” within the “hazard zonation plan”. In 

Upper Austria, Lower Austria and Burgenland, 

different approaches have been chosen to develop 

susceptibility maps (different scales, processes) 

derived from existing data sets and maps ([29] 

Posch-Trözmüller 2010): The main focus in 

Burgenland is concentrated on shallow landslides 

with an annual movement rate of 1-2cm. For 

the prediction of landslide susceptibility based 

on morphological and geological factors, the 

method called Weights of Evidence was chosen 

([16] Klingseisen et al. 2006). In Lower Austria 

susceptibility maps have been created until now 

using a heuristic approach based on geological 

expertise, historical data and interpretation of DTM 

and aerial photos ([36] Schweigl & Hervas 2009). 

To provide the municipalities with assistance in 

spatial planning, landslide susceptibility maps 

were generated for the main settled areas in Upper 

Austria (OÖ). The priority, which is a susceptibility 

class, was evaluated on the basis of the in-tensity 

and the probability of an event for each type of 

mass movement ([19] Kolmer 2009). As these 

maps include the intensity and the frequency of 

mass movements, they can be called “hazard 

maps” by definition. Nevertheless it has to be 

taken into account that the method of generating 

these maps did not include either field work or 

remote sensing techniques. The method of assessment 

is based solely on geological expertise. 

The national project of Italy, IFFI, also 

represents an important tool for landslide risk 

assessment, land use planning and mitigation 

measures. By using the information contained in 

the database of the IFFI Project and the Corine 

Land Cover Project 2000, it was possible to carry 

out an initial evaluation of the “level of attention” 

on a municipal basis. The level of attention was 

for example rated “very high”, when the landslide 

points, polygons and lines intersected with urban, 

industrial or commercial areas ([13] ISPRA 2008). 

The regions in Italy also have programs 

in cooperation with the IFFI Project (IFFI started 

as a national project and is continued by the 

separate regions), as well as with the PAI Project. 

For example, the region of Friuli Venezia Giulia 

has a landslide inventory that originated within 

these two studies, collecting data from several 

different regional offices (in particular: Protezione 

Civile della Regione and the Direzione Centrale 

Risorse Agricole, Naturali, Forestali e Montagna) 

as well as from other public subjects that work 

on the territory. It homogenizes the information 

according to national standards and surveys new 

data. The program is used for the evaluation of the 

hydrogeological hazard and risk and also to give a 

clear and updated view of the interventions made 

in the region to preserve vulnerable areas. The 

data is recorded in an official GIS structure called 

Sitgeo (Geological Service Information System). 

The main focus lies on hazard assessment at the 

scale of a slope. 

Slovenia generated a susceptibility map 

of the whole country at a scale of 1:250,000 using 

statistical analyses ([20] Komac & Ribicic 2008). 

In 2002, BGS (England) developed a nationwide 

susceptibility assessment of deterministic 

geohazards such as landslides, skrink-swell, 

etc. called GeoSure ([33] Reeves 2010). It 

was developed from the 50K digital geology 

polygons (DiGMap50), published information, 

expert judgement knowledge, national landslide 

database, national geotechnical information 

database and modified DTM. Probabilistic 

methods are used for hazard management by 

primary geohazards, deterministic methods by 

secondary geohazards.


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A number of guidelines have been published in 

Australia by the Australian Geomechanics Society 

concerning mass movements and landslide risk 

management, as well as slope management and 

maintenance. These guidelines are tools that 

were made to be introduced into the legislative 

framework of Australian governments at national, 

state and local levels, and they are also useful for 

land use planning. 

Regional susceptibility mapping of 

areas prone to landsliding is not yet commonly 

undertaken in Australia: Because of a lack of 

good inventory maps and validated inventory 

databases, landslide hazard mapping is very 

limited. Determining temporal probability is often 

not possible because of the lack of historical 

information ([25] Middleman 2007). Landslide 

mapping is generally done on a site-specific scale 

and is performed by geotechnical consultants for 

the purpose of zoning, building infrastructure 

and applying for development approvals ([25] 

Middleman 2007). Mineral Resources Tasmania 

(MRT, Department of Infrastructure, Energy and 

Resources, State Government of Tasmania) is 

the only state government agency in Australia 

to undertake several activities with respect 

to landslides, including regional mapping, 

administration of declared landslide areas and 

monitoring of a small number of problematic 

landslides. Mazengarb ([24], 2005) describes in 

detail the methodology of creating the “Tasmanian 

landslide hazard map series” that started with a 

pilot area coinciding with the Hobart municipality. 

The following basic information was used to 

create the individual landslide hazard maps 

(note: In the report the maps are called “hazard 

maps”, but on the homepage, where the maps are 

accessible via the internet, the individual maps 

are called “susceptibility maps”, but, nonetheless, 

giving “hazard zones” in the legends.): geological 

mapping (1:25,000), geomorphological mapping 

and analysis (1:5,000), landslide and engineering 

data compilation, construction of digital elevation 

models (10x10m). 

For example, a threshold slope value of 

42° was chosen for modelling rock fall source 

areas. It does not imply that rock fall will not 

occur on lower slopes, but it becomes steadily 

less likely with reduced slope angles. A simple 

modelling approach was developed for modelling 

the rock fall runout area using the direction of 

maximum downhill slope defined by an aspect 

raster and calculating with a travel angle of 30°. 

In southwestern California, soil-slip 

susceptibility maps have been produced. These 

show the relative susceptibility of hill slopes to 

the initiation of rainfall triggered soil slip-debris 

flows. They do not attempt to show the extent 

of runout of the resultant debris flows. The 

susceptibility maps were created in an iterative 

process from two kinds of information: locations 

of sites of past soil slips and aerial photographs 

taken during six rainy seasons that produced 

abundant soil slips. These were used as the basis 

for a soil slip-debris flow inventory. Also, digital 

elevation models (DTM) of the areas were used 

to analyze the spatial characteristics of soil slip 

locations. Slope and aspect values used in the 

susceptibility analysis were 10 metre DTM cells at 

a scale of 1:24,000. For convenience, the soil-slip 

susceptibility values are assembled on 1:100,000 

scale bases ([26] Morton et al. 2003). 

Comparison of hazard assessment methods 

Methods of hazard assessment used in Switzerland, 

Italy (Friuli Venezia Giulia), Australia, France and 

USA are considered in this section. First the Swiss 

and the Italian methods are compared, as these 

define intensity and probability parameters. The 

Australian method of hazard assessment, which 

is quite different from the first ones, as well as 

the method applied in the state of Washington 

(USA), is also looked into (Tab. 2). Tab. 3 gives 

an overview about hazard maps generated in the 

considered countries. 

Comparison of hazard assessment methods in Switzerland 

and Friuli Venezia Giulia (Italy) 

The hazard maps in Switzerland are compared 

especially to Friuli Venezia Giulia. More detailed 

information on the Swiss method is given by 

Raetzo & Loup in this issue [31]. The Swiss 

method ([30] Raetzo 2002) and the method used 

in Italy ([21] Kranitz & Bensi 2009) are based on 

an intensity-probability matrix. They differ from 

each other in determining the intensity and the 

probability of a landslide event. 

In Switzerland, 5 degrees of hazard are 

used. In Italy the hazard is rated in 4 classes (from 

very high [P4] to moderate [P1]). 

Concepts of hazard assessment in Switzerland 

In Switzerland the method to establish the hazard 

map was simplified as much as possible due to 

the objective of facilitating its integration into 

land use (planning). In order to have simple construction 

regulations, only 5 degrees of hazard 

were defined: high, medium, low, residual and 

neglectable hazard. The degree of hazard is 

defined in a hazard matrix based on intensity and 

probability criteria ([32] Raetzo & Loup 2009). 

For the planning of protection measures, more 

detailed investigations and calculations are done 

(e.g. all energy classes). In general the methods 

used are related to the product, scales and the risk 

in order to respect economic criteria. Applying 

this concept, low efforts were used for the swiss 

indicative map (level 1). Important efforts are taken 

when a hazard map is established or reviewed 

(level 2). Hazard maps are an accurate delineation 

of zones on scales from 1:2,000 to 1:10,000. 

Detailed analyses and engineering calculations 

are foreseen for the planning of countermeasures 

or for expertises (level 3). It is planned to apply 

this concept of increased efforts for geological 

investigations when the assessment takes place 

on the second or third level. These investigations 

include geologic mapping, geomorphologic 

analyses, monitoring, geophysics, numerical 

modelling and other methods. 

Assessment of the intensity 

(Switzerland/ Friuli Venezia Giulia) 

Intensities are assessed through a classification 

that is represented in table 2. 

The assessment of intensities in Switzerland 

is different for each process, also for floods 

and snow avalanches ([30] Raetzo 2002). For 

continuous landslide processes, the only criterion 

is the intensity. For spontaneous processes the 

intensity and the probability both ranging from 

high to low in three classes (high – medium – low) 

are needed: 

• For rock falls, the intensity is defined by 

the energy. High intensity is defined as 

e≥300kJ, which is approximately the limit 

of resistance of massive armored walls. 

• For slides, the mean long-term velocity, 

the variation of the velocity (dv, or 

acceleration), the differential movement 

(D), and the depth of the slide (T) are used 

to determine the intensity ([32] Raetzo & 

Loup 2009). 

• For flowing processes like earth flows, the 

potential thickness and the possible depth 

of the depo-sition determine the intensity.


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For landslides and rock falls the Swiss evaluation 

is normally based on intensity maps where 3 or 

more classes can be chosen. (e.g. 10-20,000 kJ 

for rock falls). 

In Italy, different methods of assessment 

are used. For example, the regional method 

of Friuli Venezia Giulia ([21] Kranitz & Bensi 

2009) for rock fall: The intensities are classified 

by different methods using several tables. For fall 

processes, a table with definition of classes of the 

geometry is determined (after [12] Heinimann et 

al. 1998). The classification takes into account the 

block size of the rocks ([21] Kranitz & Bensi 2009). 

Another table determines the velocity factor (v), 

also ranging from 1- 3, using the definitions from 

Cruden & Varnes ([9], 1996). The intensity class, 

ranging from 1- 9, is then determined with the 

geometry-velocity matrix. 

Comparison between the Swiss and the Italian 

intensity classification: 

The differences in determining the intensity 

between the Swiss ([32] Raetzo & Loup 2009) 

and the Friuli method ([21] Kranitz & Bensi 

2009) are: 

• For fall processes in the Italian method, 

the energy does not need to be calculated, 

only the block sizes and the velocity need 

to be determined, while in Switzerland the 

energy is calculated. 

• The Italian method does not differentiate 

for continuous processes. Switzerland 

uses the mean long-term velocity for these 

continuous landslides. 

• The Swiss method determines 3 intensity 

classes to apply within the hazard matrix 

for the land use planning. If protection 

measures are planned in Switzerland, all 

the energy values are taken into account. 

The Italian method determines 9 intensity 

classes. 

Assessment of the probability 

(Switzerland/ Friuli Venezia Giulia) 

Swiss method ([32] Raetzo & Loup 2009): 

The probability assessment of the Swiss method 

defines the probability in analogy to the recurrence 

periods used in flood and avalanche 

protection (30, 100, 300 years return period), 

which corresponds to yearly probabilities of 0.03, 

0.01 and 0.003. An event with a return period 

higher than 300 years is normally also considered 

for the assessment (risk analysis, residual risk,…). 

It corresponds mainly to the flood prevention 

strategy. 

The probability of an event has to be calculated 

or estimated: 

• Big events (“Bergsturz”, >1mio m3) do not 

recur. For smaller events the probability is 

defined by the elements at risk. 

• For continuous slides the probability is 1 (or 

100%), meaning that the event is happening 

already. Scenarios are defined when sudden 

landslide failure or acceleration can take 

place. When fast moving landslides (debris 

or earth slides according to Varnes) have 

long run-out distances, the process is 

moving into a flow. In this case the Swiss 

method takes into account the change from 

the first to the second move and criteria of 

the flow processes are applied (see below). 

• The probability for debris and earth flows is 

determined through field work and based 

on inventory data. Numerical modelling 

of flow processes is also used and the 

importance of these results is rising. 

Method of Friuli Venezia Giulia ([21] Kranitz & 

Bensi 2009): 

The possible frequency or occurrence probability 

is determined through the records of historical 

events. If there is a lack of sufficient historical data 

for the statistical evaluation of the return period, 

the values will be assigned by a typological 

approach based on bibliographical data inherent 

to the characteristics of temporal return of the 

various typologies of landslides. This will be 

calibrated on geomorphologic observations, 

analyses of historical photos, and aerial pictures 

(which is also the case in the Swiss method) from 

the year 1954 up to now, and historical data from 

local sources. The probability is then classified in 

4 classes: 

• high: 1-30 years (active landslides, 

continuous and/or intermittent landslides, 

quiescent – episodic with high frequency) 

• medium: 30-100 years (quiescent – episodic 

landslides with medium frequency) 

• low: 100-300 years (quiescent – episodic 

landslides with low frequency) 

• >300 years (ancient landslides or 

palaeolandslides). 

Other approaches to hazard assessment 

France 

Malet et al. ([22] 2007) describes the French 

methodology for landslide risk zoning (Plan 

de Prévention des Risques), where 3 classes of 

risk (R1, R2, R3) with specific rules for land use 

regulations and urbanism can be represented 

in a matrix depicting hazards and potential 

consequences. This qualitative method is based 

on the expert opinion of the scientist. No 

specific investigation is necessary, available data 

and reports are sufficient. The scale of work is 

specified as 1:10,000. The hazard map is an 

interpretation of the type of processes, activity, 

age and magnitude of the processes; the hazard 

map is an interpretation of the type of processes, 

activity, magnitude and frequency. The risk map is 

the crossing of the hazard map and the inventory 

map of major stakes ([22] Malet et al. 2007). 

Australia 

In the Australian guidelines for landslide 

susceptibility, hazard and risk zoning for land 

use planning, the number of events per length 

of source area per year (rock fall) or per square 

kilometer of source area per year (slides) is used 

for describing the hazard of small landslides. For 

large landslides, the annual probability of active 

sliding or the annual probability that movement 

will exceed a defined distance or the annual 

probability that cracking within a slide exceeds 

a defined length is used to describe the hazard. 

The description of the hazard should include the 

classification and the volume or the area of the 

landslides. 

Whether landslide intensity is required 

for hazard zoning is to be determined on a caseby-case 

basis. For rock fall hazard zoning, it is 

likely to be required. Therefore the frequency 

assessment is much more important for hazard 

zonation than the intensity according to AGS. 

Intensity assessment in Australia: 

The landslide intensity is assessed as a spatial 

distribution of: 

• the velocity of sliding coupled with slide 

volume or 

• the kinetic energy (e.g. rock falls, rock 

avalanches), or 

• the total displacement or 

• the differential displacement or 

• the peak discharge per unit width (m3/m/ 

sec., e.g. debris flows) 

For basic and intermediate level assessments of 

intensity, only the velocity and volume might be 

assessed. But for the advanced assessments of 

rock fall or debris flow hazard, the energy should 

be determined. In AGS ([3] 2007b) it is noted that 

“there is no unique definition for intensity. Those 

carrying out the zoning will have to decide which 

definition is most appropriate for the study”.


Seite 36 

Seite 37 

Frequency assessment in Australia: 

In AGS ([3], 2007b), the assessment of the 

frequency of a landslide event for the generation 

of hazard maps is usually determined from the 

assessment of the recurrence intervals (the average 

time between events of the same magnitude) of 

the landslides. If the variation of recurrence interval 

is plotted against magnitude of the event, a 

magnitude-frequency curve is obtained. 

The methods listed for determining the 

frequency include: historical records; sequences 

of aerial photographs and/or satellite images; 

silent witnesses; correlation with landslide 

triggering events (rain storms, earthquakes); proxy 

data (e.g. pollen deposition, lichen colonization, 

fauna assemblages in ponds generated by a 

landslide,…); geomorphologic features (ground 

cracks, fresh scarps,…); subjective assessment. 

It is further noted that “landslides of 

different types and sizes do not normally have 

the same frequency (annual probability) of 

occurrence. Small landslide events often occur 

more frequently than large ones. Different 

landslide types and mechanics of sliding have 

different triggers (e.g. rainfalls of different 

intensity, duration and antecedent conditions; 

earthquakes of different magnitude and peak 

ground acceleration) with different recurrence 

periods. Because of this, to quantify hazard, an 

appropriate magnitude-frequency relationship 

should in principle be established for every 

landslide type in the study area. In practice, the 

data available is often limited and this can only be 

done approximately.” A row of useful references 

on frequency assessment are listed in AGS ([3], 

2007b). 

In AGS ([1], 2000) it is noted that “even 

if extensive investigation is carried out, assessing 

the probability of landsliding (particularly for an 

unfailed natural slope) is difficult and involves 

much uncertainty and judgement. In recognition 

of this uncertainty, it has been common practice 

to report the likelihood of landsliding using 

qualitative terms such as “likely”, “possible” or 

“unlikely”.” 

Procedures of hazard mapping 

in the considered regions 

Tab. 3 gives an overview of hazard maps generated 

in the considered countries. 

In Germany a recommendation on how to create 

a susceptibility map is given by the “Geohazards” 

team of engineering geologists of German federal 

governmental departments of geology ([37] SGD 

2007). In 2007, the LfU completed the Landslide 

susceptibility map of Oberallgäu (Bavaria). For 

this map, the processes of rock falls, superficial 

landslides and deep seated landslides were 

treated separately. The susceptibility maps for rock 

falls and superficial landslides were created using 

modelling, whereas the susceptibility map for 

deep seated landslides was created empirically, 

assuming that deep seated landslides tend to occur 

in areas already affected by landslides in the past, 

but taking into consideration that process areas 

can expand during reactivation of a landslide. The 

basic data used for the investigations contained 

the following: topographic map 1:25,000, raster 

format; geological map 1:25,000 or 1:50,000 and 

also maps in smaller scales where the detailed 

maps were not available, vector format; DTM, 

10m raster data; aerial photographs 1:18,000 and 

orthophotos; data on forests; GEORISK data (BIS- 

BY); data on catchment areas; historical data. 

In Austria only the Austrian Service for 

Torrent and Avalanche Control (WLV) generates 

hazard maps, called “Gefahrenzonenkarte” or 

“hazard zone maps” for floods, avalanches and 

debris flows within the “Hazard zonation plan” 

(“Gefahrenzonenplan”). This is regulated by law 

(Forest Act BGBL. 440/1975). The implementation 

is regulated by a decree (“Verordnung des 

Bundesministeriums für Land- und Forstwirtschaft, 

1976“, BGBl. Nr. 436/1976). The scale usually 

ranges between 1:2,000 and 1:5,000, it must not be 

smaller than 1:50,000. The map gives information 

about the determined effects in the relevant area 

of catchment areas (torrent buffer areas) in red 

and yellow hazard zones. The design event is 

determined by a return period of 150 years. 

In the red hazard zone, infrastructures 

cannot be maintained or can only be maintained 

with a very high effort due to the high intensity 

or a high recurrence of avalanches or torrential 

events. 

The yellow hazard zone includes all 

other areas affected by avalanches and torrents. 

The constant use of these areas by infrastructures 

is affected due to these hazards. The hazard 

zone map also delineates blue areas (for the 

implementation of technical or forestal measures 

as well as protective measures), as well as brown 

and violet reference areas. 

The brown reference areas are areas 

presumably affected by other hazards than 

torrents or avalanches, like rock fall or landslides. 

The violet reference areas are areas, where soil 

and terrain have to be protected in order to keep 

up their protective function. 

In Switzerland, the Federal Office for 

the Environment FOEN (Bundesamt für Umwelt, 

BAFU) is responsible for creating guidelines 

concerning protection against natural hazards 

(floods, mass movements, snow avalanches). The 

concepts are similar for these processes to reach 

a certain level of protection. Protection against 

natural hazards takes place on the principle of 

integral risk management, taking into account: 

• Prevention of an event 

• Conflict management during an event 

• Regeneration and reconstruction after 

an event. 

The Swiss regulations are described in more detail 

by Raetzo in this issue [31]. 

In some regions of Italy the hazard is 

assessed using the Swiss method ([30] Raetzo 

2002). This method is similar to the method planned 

by the Italian legislative body for hydrogeological 

risk assessment. Appropriate changes have been 

introduced in order to standardize these aspects 

and contextualize the method for territorial 

jurisdiction ([21] Kranitz & Bensi 2009). Four 

classes of hazards are distinguished, ranging 

from very high (P4 “molto elevata”), high (P3 

“elevata”), medium (P2 “media”), to moderate (P1 

“moderata”). 

The French hazard map, PPR, Plan 

de prevention des risques, is made by the local 

authorities (mayors), but with support by national 

agencies like CEMAGREF or agencies of the 

departments. It was introduced in 1995. Made 

by the municipalities at a scale of 1:10,000 

-1:25,000, the plans need to be authorized 

by the prefects in collaboration with the local 

authorities and the civil society, such as insurance 

companies. The PPR gives information about the 

identification of danger zones; 3 classes of risk 

with specific rules for land use regulations and 

urbanism can be represented. The method is a 

qualitative method based on the expert judgment 

of the scientist. There are PPRs for floods, mass 

movements, avalanches and wood fires. Nonobservance 

of the PPR has legal consequences. 

In Spain the Geological Institute of 

Catalonia (IGC) is responsible to “study and 

assess geological hazards, including avalanches, 

to propose measures to develop hazard forecast, 

prevention and mitigation and to give support 

to other agencies competent in land and urban 

planning, and in emergency management” ([28] 

Oller et al. 2010). Therefore, the IGC is charged 

with making official hazard maps with such 

finality. These maps comply with the Catalan


Seite 38 

Seite 39 

Urban Law (1/2005), which indicates that in those 

places where a risk exists, building is not allowed. 

For hazard mapping, the work is done on two 

scales: land planning scale (1:25,000), and urban 

scale (1:5,000 or more detailed). These scales 

imply different approaches and methods to obtain 

hazard parameters. The maps are generated in 

the framework of a mapping plan or as the final 

product of a specific hazard report. 

The Australian AGS guidelines ([1] AGS, 

2000, [2]- [6] AGS 2007a-e) provide for a hazard 

zonation at a local (1:5,000 -1:25,000) and a site 

specific (>1:5,000, typically 1:5,000 -1:1,000) 

scale with 5 hazard descriptors: very high – high 

– moderate – low – very low. 

The state of Washington (USA) generated 

Informationsebene 

Interpretationsebene / Bewertungsebene 

quantitativ qualitativ / semiquantitativ 

Ereigniskataster 

Gefahrenhinweiskarte 

Fig. 1: Workflow of hazard mapping. ([18] Kociu et al. 2010) 

Ereigniskarte 

Grunddispositionskarte 

Abb. 1: Flussdiagramm zum Prozess Gefahrenkartierung. ([18] Kociu et al. 2010) 

hazard zonation maps at a scale of 1:12,000. 

The hazard assessment included evaluating a 

“landslide frequency rate (LFR)“ and a “landslide 

area rate for delivery (LAR)”. The LFR is obtained 

by taking the number of delivering landslides 

per landform, divided by the total area of that 

landform, and normalized to the period of study. 

The LAR is the area of delivering landslides 

normalized to the period of study and the area of 

each landform. The resulting values are multiplied 

by one million for easier interpretation. 

In California soil-slip susceptibility maps 

were produced at a scale of 1:24,000 delineating 

the susceptibility in 3 classes: low, moderate and 

high. They give information about the relative susceptibility 

of hill slopes to the initiation sites of 

Prozesshinweiskarte 

(Karte der Phänomene) 

Dispostionskarte 

Gefahrenpotentialkarte 

(Karte der potentiellen Wirkungsbereiche) 

Gefahrenkarte 

Risikokarte 

Thematische 

Inventarkarte 

Erweiterte 

Dispositionskarte 

Standortparameter 

und -verhältnisse 

rainfall-triggered soil-slip debris flows ([26] Morton 

et al., 2003). 

The state of Utah prepared a landslide 

susceptibility map for the whole state at a scale 

of 1:500,000 for deep seated landslides, based 

on existing landslides and slope angle thresholds 

for different geologic units. The susceptibility is 

delineated in 4 classes: high – moderate – low – 

very low ([10] Giraud & Shaw, 2007). 

Conclusion and recommendations 

Guzzetti ([11], 2005) discusses hazard assessment 

in his thesis: “Despite the time [since the definition 

of “landslide hazard” given by Varnes and the 

IAEG Commission on Landslides and other Mass 

Movements ([39], 1984)] and the extensive list 

of published papers – most of which, in spite of 

the title or the intention of the authors, deal with 

landslide susceptibility and not with landslide 

hazard”, landslide hazard assessment at the basin 

scale is sparse. And further: “This is largely due 

to difficulties associated with the quantitative 

determination of landslide hazard.” In carrying out 

the literature survey, this unfortunately proved to 

be true and contributed to the confusion existing 

with definitions ([29] Posch-Trözmüller 2010). 

The differences call first for a national 

harmonization and second for international 

comparable methods (minimal requirements). 

To assess landslide hazards, the 

geological, morphological, hydrogeological and 

hydrological conditions must be known and 

analysed: The differences regarding acquisition of 

information and assessment of the susceptibility/ 

hazard of slopes to landslides and rock fall shown 

in the chapter above call for a “harmonization” 

of the different methods (e.g. parameters, 

minimal requirements). Hazard assessment 

needs information about possible scenarios. 

Landslide inventories sustain landslide knowledge 

through time and represent the main resource for 

susceptibility/hazard assessment. The evidence 

identified in the field are the facts dealing with 

natural hazards. Inventories are the essential base 

for accurate hazard/risk assessment and have 

therefore to be established by authorities. 

The variability of phenomena of mass 

movements makes regulations concerning 

methods of hazard assessment difficult. Guidelines 

regarding hazard assessment should declare the 

minimal requirements taking into account the 

final objective and the scale of product.


Countries Austria D CH SLO IT F AUS USA 

GBA NÖ K MM S By CH SLO IT F AUS O W U 

Inventory x x x x x x x x x x x x x x 

Basic information where x x x x x x x x x x x x x x 

when x x x x x x x x x x x x x x 

what x x x x x x x x x x x x x x 

why x x x x x x x x x x 

who x x x x x x x x x x x x 

reported when x x x x x x x x 

Landslide conditions activity x x x x x x x x x 

geometry x x x x x x x x x x x x x 

slope position x x x x x x 

approx. original slope x x x 

site description x x x x 

depth to bedrock x x 

depth to failure 

plane 

slope aspect x x x x x x 

slope x x x 

Geology in general x x x x x x x x x 

Geology, specified 

geologic/ tectonic 

unit 

x x x x x x x 

lithology/ stratigraphy x x x x x x x 

bedding attitude x x x x 

weathering x x x 

geotechnical 

properties 

x x x x x x x x 

x 

geotechnical 

parameters 

x x x 

rock mass structure x x x 

joints/ joint spacing x x x x 

discontinuities x x x 

structural 

contributions 

x x x 

Land cover/ use x x x x x 

Hydrogeology x x x x 

Relationship to rainfall x x x 

Classification of mass 

movements 

x x x 

Classification type x x x x x x x x x x x x 

rate of movement x x x 

material x x x x 

water content x x x 

Causes, Trigger x x x x x x x x x x 

Precursory signs x 

Silent witnesses x 

Damage x x x x x x x x x x x 

"Hazard" to infrastructure x x x x 

Remedial measures x x x x x 

Costs of measures and 

investigation 

x x x 

Methods used x x x x x x x x x 

Degree of precision 

info/ reliability 

x x x x 

Reports etc. x x x x x x x x 

Tab. 1: Comparison of information collected for different inventories 

Tab. 1: Vergleich der Informationen in Ereigniskatastern 

Seite 40 

Seite 41


Switzerland low intensity moderate intensity high intensity 

rock fall E


Seite 44 

Seite 45 



Countries/ projects 

Comparison of 

hazard maps 

USA: 

Washington 

Australia: 

AGS 

France: 

PPR 

Italy: 

Guzzetti 

Italy: 

Friuli, Veneto 

Switzerland: 

FOEN/BAFU 

Austria: 

WLV 

1:12,000 

1:5,000- 

1:25,000 

1:10,000 

(urban), 

-1:25,000 

(rural) 

national is 

possible, 

regional 

1:2,000- 1:10,000 detail 

1:2,000- 

1:5,000 

Scale 

eventually x x 

Basic data: 

susceptibility map 

Basic data: inventory x x x x x x x 

30 years 

100 years 

300 years 

>300 years 

30 years 

100 years 

300 years 

(Residual risk zones 

for RP>300y) 

Return periods 

considered for land 

use (probability) 150 years 

statistical 

statistic and 

empirical 

qualitative 

empirical, 

probabilistic 

quantitative, 

statistical 

(incl. field 

investigation) 

quantitative, 

statistic, qualitative 

(incl. field 

investigation) 

quantitative, 

statistic, 

empirical 

Method 

(assessment, 

modelling) 

5 4 5 2 (3) 5 3 

2 (for torrent 

and debris 

flow), 

indication for 

landslides and 

rock fall 

Legend: 

Levels of hazard 

Tab. 3: Comparison of different hazard maps, their scales and legends (levels of hazard) 

Tab. 3: Vergleich von verschiedenen Gefahrenkarten, Maßstäben und Legenden (Grad der Gefahren) 

Richard Bäk 

Amt der Kärntner Landesregierung 

Abt. 15 Umwelt 

Unterabteilung Geologie und Bodenschutz 

Flatschacher Straße 70, A – 9020 Klagenfurt 

Karl Mayer 

Bayerisches Landesamt für Umwelt 

Abt. 6 Wasserbau, Hochwasserschutz, 

Gewässerschutz 

Ref. 61 Hochwasserschutz und alpine 

Naturgefahren 

Lazarettstraße 67 

D – 80636 München 

Gerlinde Posch-Trözmüller 

Geologische Bundesanstalt 

Fachabteilung Rohstoffgeologie 

Neulinggasse 38, A-1030 Wien 

Andreas von Poschinger 

Bayerisches Landesamt für Umwelt 

Abt. 10 Geologischer Dienst 

Ref.106 Ingenieurgeologie, Georisiken, 

Lazarettstraße 67, D – 80636 München 

Hugo Raetzo 

Federal Office for the Environment FOEN 

Bundesamt für Umwelt BAFU 

CH - 3003 Bern, Schweiz 

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Guideline for Landslide Susceptibility, Hazard and Risk Zoning for Land 

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Commentary on Guideline for Landslide Susceptibility, Hazard and 

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Australian Geomechanics, Vol 42, No 1, March 2007. 

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Practice Note Guidelines for Landslide Risk Management. Australian 

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[30] RAETZO, H.: 

Hazard assessment in Switzerland – codes of practice for mass movements, 

International Association of Engineering Geology IAEG Bulletin, 2002. 

[31] REATZO, H. & LOUP, B.: 

Geological hazard assessment in Switzerland (this issue) 

[32] RAETZO, H. & LOUP, B. ET AL.; BAFU: 

Schutz vor Massenbewegungen. Technische Richtlinie als Vollzugshilfe. 

Entwurf 9. Sept. 2009. 

[33] REEVES, H.: 

Geohazards: The UK perspective. Vortrag Workshop AdaptAlp, 17.3.2010, 

Bozen 2010. 

[34] RUDOLF-MIKLAU F. & SCHMIDT F.: 

Implementation, application and enforcement of hazard zone maps 

for torrent and avalanches control in Austria, Forstliche Schriftenreihe, 

Universität für Bodenkultur Wien, Bd. 18, p. 83-107, 2004. 

[35] RUFF, M.: 




[36] SCHWEIGL, J.; HERVAS, J.: 

Landslide Mapping in Austria. JRC Scientific and Technical Report EUR 

23785 EN, Office for Official Publications of the European Communities, 

61 pp. ISBN 978-92-79-11776-3, Luxembourg, 2009. 

[37] SGD, PERSONENKREIS GEOGEFAHREN: Geogene Naturgefahren in 

Deutschland- Empfehlungen der Staatlichen Geologischen Dienste (SGD) 

zur Erstellung von Gefahrenhinweiskarten., 2007. 

[38] TILCH, N.: 

Datenmanagementsystem GEORIOS (Geogene Risiken Österreich). Vortrag 

im Rahmen des Landesgeologentages 2009, 26.2.2009, St. Pölten 2009. 

[39] VARNES, D.J. AND IAEG COMMISSION ON LANDSLIDES AND 

OTHER MASS-MOVEMENTS: 

Landslide hazard zonation: a review of principles and practice. The 

UNESCO Press, Paris, 1984.


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In den Bergregionen treten an Steilhängen verschiedene Arten von Massenbewegungen 

auf, die Wasser und Sedimente mit sich führen: Muren, Bergsturz und Steinschlag. Das 

Ziel dieser Abhandlung ist es, einen kurzen Überblick über die vergangenen Analysen der 

Gefahren von Hangmassenbewegungen zu geben. Obwohl der Schwerpunkt auf Bergstürzen 

liegt, können die präsentierten Ansätze auch zur Gefahrenbeurteilung von Muren 

und Steinschlag verwendet werden. Insbesondere Bergstürze und Muren sind sehr häufig 

miteinander verflochten. Im Folgenden wird „Bergsturz“ im weiteren Sinn als ein Begriff 

verwendet, der nicht nur auf einen Erdrutsch zu beziehen ist, sondern auch auf andere 

Hangmassenbewegungen. 

Schlüsselwörter: Bergstürze, Muren, Felssturz, numerische Ansätze, Bergsturzgefahrenanalyse 

MATEJA JEMEC, MARKO KOMAC 

An Overview of Approaches for 

Hazard Assessment of Slope Mass Movements 

Ein Überblick über die Ansätze zur 

Gefahrenbeurteilung von Massenbewegung 

Summary: 

In mountainous areas, various types of mass movements occur on steep slopes involving 

water and sediment: debris flows, landslides and rockfalls. The aim of this paper is to gather 

a short overview of the past analyses that dealt with the hazard assessment of slope mass 

movements. Although the main focus is on landslides, the approaches presented can be used 

to assess debris flows and rockfall hazards. In particular, landslides and debris flow are very 

often interlaced between each other. In the following text, the term “landslide” will be used 

as a term that might not always be strictly connected to only landslides but also to other 

slope mass movements. In a way it has a broader meaning. 

Keywords: landslides, debris-flows, rockfall, numerical approaches, landslide hazard assessment 

1. The “Early Ages” 

The first extensive papers on the use of spatial 

information in a digital context for landslide 

susceptibility mapping date back to the late 

seventies and early eighties of the last century. 

Among the pioneers in this field were Carrara 

et al. (1977) in Italy and Brabb et al. (1978) in 

California. Nowadays, practically all research 

on landslide susceptibility and hazard mapping 

makes use of digital tools for handling spatial data 

such as GIS, GPS and Remote Sensing. These tools 

also have defined, to a large extent, the type of 

analysis that can be carried out. It can be stated 

that to a certain degree the capability of GIS 

tools and the accuracy of the in-situ and remote 

sensing data have determined the current state of 

the art in landslide hazard and risk assessment. 

Many publications about landslides and some 

worldwide landslide research problems can be 

found in the literature of Einstein (1988), Fell 

(1994), Dai et al. (2002) and Glade et al. (2005). 

2. Terminology 

The term landslide was defined by Varnes and 

IAEG (1984) as “almost all varieties of mass 

movements on slopes, including rock-fall, topples 

and debris flow, that involve little or no true 

sliding”. Cruden (1991) moderated the accepted 

definition as “the movement of a mass of rock, 

earth or debris down a slope”. Later different 

working groups were established to support a 

specific level of standardisation in fields related 

to landslides (UNESCO, IUGS, ISSMGE, ISRM 

and IAEG) and created the JTC (Joint Technical 

Committee on Landslides and Engineered Slopes), 

which continues to work for the standardisation 

and promotion of research on landslides among 

the different disciplines. A large set of definitions 

was later presented by ISSMGE TC32 (Technical 

Committee on Risk Assessment and Management, 

2004) where international terms recognized for 

hazard, vulnerability, risk and disaster can also 

be found. Since these definitions were published, 

many approaches have been implemented 

(Einstein, 1988; Fell, 1994; Soeters and van Westen, 

1996; Wu et al., 1996; Cruden and Fell, 1997; van 

Westen et al., 2003; Lee and Jones, 2004; Glade et 

al., 2005) allowing one to conclude that nowadays 

definitions regarding landslides risk assessment 

are generally accepted. The latest information of 

guidelines for landslide susceptibility, hazard and 

risk zoning are published by JTC-1 (2008) and van 

Westen et al. (2008).


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Data layer and types Accompanying data in tables Used methods for data collecting 

1. Landslide occurrence 

Landslides Type, activity, depth, dimensions, etc Fieldwork, orthophoto, satellite images 

2. Environmental (preparatory) factors 

Terrain mapping units Units description In-situ survey (fieldwork), satellite images 

Geomorphological units Geomorphological description Ortophoto, fieldwork, high resolution DEM 

Digital elevation model (DEM) Altitude classes SRTM DEM data, topographic map 

Slope map Slope angle classes With GIS form DEM 

Aspect map Slope direction classes With GIS form DEM 

Slope length Slope length classes With GIS form DEM 

Slope shape Concavity/convexity With GIS form DEM 

Internal relief Altitude/area classes With GIS form DEM 

Drainage density Longitude/area classes With GIS form DEM 

Lithologies 

Soils and material sequences 

Structural geological map 

Lithology, rock strength, weathering 

process 

Soils types, materials, depth, grain 

size, distribution, bulk density 

Fault type, length, dip, dip direction, 

fold axis 

Fieldwork and laboratory tests, archives, 

orthophoto 

Modelling form lithological map, 

geomorphological map and slope map, 

fieldwork and laboratory analysis 

Fieldwork, satellite images, orthofoto 

Vertical movements Vertical movements, velocities Geodetic data, satellite data 

Land use map Land use type, tree density root depth Satellite images, orthofoto, fieldwork 

Drainage Type, order and length Orthophoto, topographic map 

Catchment areas Order, size Orthophoto, topographic map 

Water table Depth of water table in time Hydraulic stations 

3. Triggering factors 

Rainfall and maximum probabilities Precipitation in time Meteorological stations and modelling 

Earthquakes and seismic 

acceleration 

4. Elements at risk 

Earthquakes database and 

maximum sesismic acceleration 

Seismic data, engineering geological data 

and modelling 

Population Number, sex, age, etc. Statistics information 

Transportation system and facilities 

Lifeline utility system 

Roads and railroad types, facilities 

types 

Types of lifeline network and 

capacity of fascilities 

Atlas, topographic map, local 

information 

Atlas, topographic map, local 

information 

Building Type of structure and occupation Topographic map, Housing information 

Industry Industry production and type Atlas, topographic map, local information 

Services facilities 

Number and type of health, 

educational, cultural and sport 

facilities 

Atlas, topographic map, local information 

Tourism facilities Type of touristy facilities Atlas, topographic map, local information 

Natural resources 

Area without natural resources 

combined 

Atlas, topographic map, local information 

Tab. 1: Summary of data needed for landslide hazard and risk assessment. Adapted from Soeters and van Westen (1996). 

Tab. 1: Zusammenfassung der Daten für Erdrutsch-Gefährdungs- und Risikoanalyse. Adaptiert von Soeters und van Westen (1996). 

Landslide related data can be grouped into four 

main sets, Table 1 (Soeters and van Westen, 1996). 

Debris flows are processes that 

have several sub-categories and different 

characteristics. Debris flows are gravity-induced 

mass movements, intermediate between land 

sliding and water flooding, with mechanical 

characteristics different from either of these 

processes (Johnson, 1970). According to Varnes 

(1978), debris flow is a form of rapid mass 

movement of rocks and soils in a body of granular 

solid, water, and air, analogous to the movement 

of liquids. In the landslide classification of Cruden 

and Varnes (1996), debris flows are flow-like 

landslides with less than 80% of sand and finer 

particles. Velocities vary between very rapid and 

extremely rapid with typical velocities of 3 m/min 

and 5 m/sec, respectively. Landslides and debris 

Fig. 1: Classification of slope mass movements as a ratio of solid fraction and material type. 

Modified after Coussot and Meunier (1996). 

Abb. 1: Klassifikation von Massenbewegungen als Verhältnis von Geschiebefraktion und Materialart. 

Modifiziert nach Coussot und Meunier (1996). 

flow are very often interlaced between each 

other (Fig.1). In many cases, heavy precipitation 

is recognised as the main cause, and thresholds 

under different climatic conditions have been 

empirically evaluated (Caine, 1980; Canuti et 

al., 1985; Fleming et al., 1989; Mainali and 

Rajaratnam, 1994; Anderson, 1995; Cruden and 

Varnes, 1996; Finlay et al., 1997; Crosta, 1998; 

Crozier, 1999; Dai et al., 1999; Glade, 2000; 

Alcantara-Ayala, 2004; Fiorillo and Wilson, 2004; 

Lan et al., 2004; Malet et al., 2005; Wen and 

Aydin, 2005). Landslides may mobilise to form 

debris flows by three processes: (a) widespread 

Coulomb failure within a sloping soil, rock, or 

sediment mass, (b) partial or complete liquefaction 

of the mass by high pore-fluid pressure, and (c) 

conversion of landslide translational energy to 

internal vibrational energy (Iverson et al., 1997).


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Rockfall is one of the most common mass 

movement processes in mountain regions and is 

defined as the free falling, bouncing or rolling 

of individual or a few rocks and boulders, with 

volumes involved generally being < 5 m 3 (Berger 

et al., 2002). Numerous studies exist concerning 

various aspects of rockfall, such as the dynamic 

behaviour (Ritchie, 1963; Erismann, 1986; Azzoni 

et al., 1995), boulder reaction during ground 

contact (Bozzolo et al., 1986; Hungr and Evans, 

1988; Evans and Hungr, 1993), or runout distances 

of falling rocks (Kirkby and Statham, 1975; Statham 

and Francis, 1986; Okura et al., 2000). Much 

research was also done on the possible triggers 

of rockfall, such as freeze-thaw cycles (Gardner, 

1983; Matsuoka and Sakai, 1999; Matsuoka, 

2006), changes in the rock-moisture level (Sass, 

2005), the thawing of permafrost (Gruber et al., 

2004), the increase of mean annual temperatures 

(Davies et al., 2001), tectonic folding (Coe and 

Harp, 2007) or the occurrence of earthquakes 

(Harp and Wilson, 1995; Marzorati et al., 2002). 

In addition, several studies exist on the long-term 

accretion rates of rockfall (Luckman and Fiske, 

1995; McCarroll et al., 1998). Furthermore, since 

the late 1980s, the field of numeric modelling 

has become a major topic in the field of rockfall 

research (Zinggerle, 1989; Guzzetti et al., 2002; 

Dorren et al., 2006; Stoffel et al., 2006). 

3. Numerical approaches to landslide hazard 

assessment 

According to Van Westen (1993), the landslide 

hazard assessment methods have been divided 

into four groups of analysis. We’ve added an 

additional group – Artificial Neural Networks. The 

selection of one method over another depends on 

several factors (the data costs and availability, the 

scale, the output requirements, the geological and 

geomorphological conditions, the tectonogenetic 

and morphogenetic behaviour of the landslides, 

and computing capabilities of software and 

hardware tools). 

Firstly, inventory analysis, which are 

based on the analysis of the spatial and temporal 

distribution of landslide attributes and such 

inventories are the basis of most susceptibility 

mapping techniques. On detailed landslide 

inventory maps, the basic information for 

evaluating and reducing landslide hazards on 

a regional or local level may be provided. Such 

maps include the state of activity, certainty of 

identification, dominant type of slope movement, 

primary direction, and estimated thickness of 

material involved in landslides, and the dates of 

known activity for each landslide (Wieczorek, 

1984). 

Secondly, the popular heuristic analysis 

(Castellanos and van Westen, 2003; R2 Resource 

Consultants, 2005; Ruff and Czurda, 2007; 

Firdaini, 2008) based on expert criteria with 

different assessment methods. The landslide 

inventory map is accompanied with preparatory 

factors to be the main input for determining 

landslide hazard zoning. Experts then define the 

weighting value for each factor. 

Many researchers utilize statistical 

analysis (Neuland, 1976; Carrara, 1983; Pike, 

1988; Carrarra et al., 1991; van Westen, 1993; 

Chung & Fabbri, 1999; Gorsevski et al., 2000; 

Dhakal et al., 2000; Zhou et al., 2003; Saha et al., 

2005; Guinau et al., 2007; Komac and Ribičič, 

2008; Magliulo et al., 2008; Miller and Burnett, 

2008; Pozzoni et al., 2009; Komac et al., 2010), 

where several parameter maps are surveyed to 

apply bivariate and multivariate analysis. The 

key of this method is the landslide inventory map 

when the past landslide occurrences are needed 

to forecast future landslide areas. 

The next approach is deterministic 

analysis (van Westen, 1994; Terlien et al., 1995; 

van Westen and Terlien, 1996; Soeters and Westen, 

1996; van Asch et al., 1999; Zaitchik et al., 2003; 

Mazengarb, 2004; Schmidt and Dikau, 2004; 

Mayer et al., 2010), which is based on hydrological 

and slope instability models to evaluate the safety 

factor. Montgomery et al. (1994, 1998 and 2000) 

have attributed a great importance to precipitation 

and many other investigations have also been 

carried out about the relationship between rainfall 

and landslides (Crozier, 1999; Lida, 1999; Dai 

and Lee, 2001; Guzzetti et al., 2007). For rainfall 

induced failures, these models couple shallow 

subsurface flow caused by rainfalls of various 

return periods, predicted soil thickness and soil 

mantle landslides. Numerous studies have used 

rainfall characteristics, such as duration, intensity, 

maximum and antecedent rainfall during a 

particular period, to identify the threshold value for 

landslide initiation. Many authors (Caine, 1980; 

Caine and Mool, 1982; Brabb, 1984; Cannon 

and Ellen, 1985; Jakob and Weatherly, 2003) 

applied the rainfall intensity duration equation 

to estimate the threshold. With regard to specific 

rainfall characteristics, Wieczorek and Sarmiento 

(1983) used total rainfall duration before specific 

rainfall intensity occurs; Govi et al. (1985) applied 

total rainfall during a specific period after rainfall 

starts; and Crozier (1986) utilized the ratio of 

total rainfall to antecedent rainfall. Guzzetti et 

al. (2004) identified the local rainfall threshold 

on the basis of local rainfall and landslide record 

and concluded that landslide activity in Northern 

Italy initiates 8-10 hours after the beginning of a 

storm. However, many other investigations have 

been published about the relationship between 

rainfall and landslides and attribute a large 

impact to precipitation for the time duration of 

landslides (Carrara, 1991; Mongomery et al., 

1994, 1998; Terlien et al., 1995; Crozier, 1999; 

Laprade et al., 2000; Alcantara-Ayala, 2004; Coe 

et al., 2004; Fiorillo and Wilson, 2004; Lan et al., 

2004; Wen and Aydin, 2005; Zezere et al., 2005; 

Giannecchini, 2006; Jakob et at., 2006). While 

some of them deal with specific cases, others are 

more concerned with the statistical relationship 

for creating correlations models and even produce 

forecasting models based on rainfall threshold 

values. 

One of the relatively new methods 

applied to landslide hazard and susceptibility 

assessment are artificial neural network (ANN) 

tools. ANN is a useful approach for problems 

such as regression and classification, since it 

has the capability of analyzing complex data 

at varied scales such as continuous, categorical 

and binary data. The concept of ANN is based on 

learning form data with known characteristics to 

derive a set of weighting parameters which are 

used subsequently to recognize the unseen data 

(Horton, 1945). 

Lee et al. (2003b) developed landslide 

susceptibility analysis techniques using a multilayered 

perception (MLP) network. The results 

were verified by ranking the susceptibility index 

in classes of equal area and showed satisfactory 

agreement between the susceptibility map and 

the landslide location data. Lee et al. (2003a) 

obtained landslide susceptibility by using neural 

network models and compared neural models with 

probabilistic and statistical ones. They also show a 

combination of ANN for determination of weights 

used spatial probabilities to create a landslide 

susceptibility index map (Lee et al., 2004). Rainfall 

and earthquake scenarios as triggering factors for 

landslides have been used in hazard assessment 

with ANNs (Lee and Evangelista, 2006; Wang and 

Sassa, 2006). Several studies recognize ANN as a 

promising tool for these applications and most of 

them use a Multi layer Perceptron (MLP) network 

and a back propagation algorithm for training 

the network (Rumelhart et al., 1986; Arora et 

al., 2004; Ercanoglu, 2005; Ermini et al., 2005;


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Numerical approach Basic description of approach References 

Inventory analysis 

Heuristic analysis 

Statistical analysis 

Deterministic analysis 

rainfall 

Artificial neural 

network (ANN) 

Analysis of the spatial and 

temporal distribution of 

landslide attributes 

Based on expert criteria with 

different assessment methods 

Several parameter maps are 

surveyed to apply bivariate 

and multivariate analysis 

Apply hydrological and slope 

instability models to evaluate 

the safety factor 

Use rainfall characteristic to 

identify the threshold value for 

landslide initiation 

Learning from data with 

known characteristics to derive 

a set of weighting parameters, 

which are used subsequently 

to recognize the unseen data 

Wieczorek (1984) 

Castellanos and van Westen (2003); 

R2 Resource Consultants (2005); Ruff and 

Czurda (2007); Firdaini (2008) 

Neuland (1976); Carrara (1983); Pike 

(1988); Carrarra et al. (1991); van Westen 

(1993); Chung and Fabbri (1999); Gorsevski 

et al. (2000); Dhakal et al. (2000); Zhou et 

al. (2003); Saha et al. (2005); Guinau et al. 

(2007); Komac and Ribičič (2008); Magliulo 

et al. (2008); Miller and Burnett (2008); 

Pozzoni et al. (2009); Komac et al. (2010) 

van Westen (1994); Terlien et al. (1995); 

van Westen and Terlien (1996); Soeters 

and Westen (1996); van Asch et al. (1999); 

Zaitchik et al. (2003); Mazengarb (2004); 

Schmidt and Dikau (2004); Mayer et al. (2010) 

Caine (1980); Caine and Mool (1982); 

Wieczorek and Sarmiento (1983); Brabb 

(1984); Cannon and Ellen (1985); Govi et 

al. (1985); Crozier (1986); Carrara (1991); 

Terlien et al. (1995); Montgomery et al. 

(1994, 1998 and 2000); Crozier (1999); 

Lida (1999); Laprade et al. (2000); Dai 

and Lee (2001); Jakob and Weatherly 

(2003); Alcantara-Ayala (2004); Coe et 

al. (2004); Fiorillo and Wilson (2004); 

Guzzetti et al. (2004); Lan et al. (2004); 

Zezere et al. (2005); Wen and Aydin (2005); 

Giannecchini (2006); Jakob et al. (2006); 

Guzzetti et al. (2007) 

Horton (1945); Rumelhart et al. (1986); 

Ercanoglu and Gokceoglu (2002); Lee et al. 

(2003a); Lee et al. (2003b); Lu (2003); Arora 

et al. (2004); Lee et al. (2004); Neaupane and 

Achet (2004); Catani et al. (2005); Ercanoglu 

(2005); Ermini et al. (2005); Gomez and 

Kavzoglu (2005); Miska and Jan (2005); Wang 

et al. (2005); Yesilnacar and Topal (2005); 

Kanungo et al. (2006); Lee and Evangelista 

(2006); Lui et al. (2006); Melchiorre et al. 

(2006, 2008); Wang and Sassa (2006); Lee 

(2007); Pradhan and Lee (2007,2009a, 2009b, 

2009c); Nefeslioglu et al. (2008); Pradhan et 

al. (2009); Youssef et al. (2009) 

Tab. 2: Review of numerical approaches to landslide hazard assessment with short description of approach and references. 

Tab. 2: Überprüfung von numerischen Ansätzen zur Gefahrenabschätzung von Rutschungen mit einer kurzen Darstellung des Ansatzes 

und Referenzen. 

Gomez and Kavzoglu, 2005; Wang et al., 2005; 

Pradhan and Lee, 2007, 2009a, 2009b, 2009c; 

Pradhan et al., 2009; Youssef et al., 2009). Ermini 

et al. (2005) and Catani et al. (2005) used unique 

conditions units for the terrain unit definition in 

ANNs analysis. More critical analyses compare 

ANN techniques with other methods such as 

logistic regression, fuzzy weighing and other 

statistical methods (Ercanoglu and Gokceoglu, 

2002; Lu, 2003; Neaupane and Achet, 2004; 

Miska and Jan, 2005; Yesilnacar and Topal, 2005; 

Kanungo et al., 2006; Lee, 2007). In the neural 

network method, Nefeslioglu et al. (2008) showed 

that ANNs give a more optimistic evaluation of 

landslide susceptibility than logistic regression 

analysis. Melchiorre et al. (2006) did further 

research on the behaviour of a network with 

respect to errors in the conditioning factors by 

performing a robustness analysis and Melchiorre 

et al. (2008) improved the predictive capability 

and robustness of ANNs by introducing a cluster 

analysis. Neaupane and Achet (2004) used 

ANN for monitoring the movement. Moreover, 

Kanungo et al. (2006) showed that a landslide 

susceptibility map derived from combined 

neural and fuzzy weighting procedure is the best 

amongst the other weighting techniques. Lui et 

al. (2006) assessed the landslide hazard using 

ANNs for a specific landslide typology (debris 

flow), considering among the triggering factors 

frequency of flooding, covariance of monthly 

precipitation, and days with rainfall higher than a 

critical threshold. 

4. Approaches to landslide hazard assessment 

The landslide susceptibility assessment is a 

particular step in the landslide hazard assessment 

and is usually based on the comparison of 

the previously surveyed landslides and the 

conditional or preparatory causal factors. With 

this combination a GIS is obtained in a landslide 

susceptibility map. In susceptibility analyses, 

triggering causal factors are often not considered. 

Some research has been done specifically related 

to the landslide susceptibility assessment (Lee et 

al., 2003; Sirangelo and Braca, 2004; Guzzetti 

et al., 2006). Several countries have published 

national landslide susceptibility maps that are 

based on their national landslide inventory 

(Brabb et al., 1999; Guzzetti, 2000; Komac and 

Ribičič, 2008). One of the proven techniques for 

landslide susceptibility assessment is the weights 

of evidence (WofE) modelling. Many landslide 

susceptibility have been carried out using this 

method (van Westen, 1993; Fernandez, 2003; van 

Westen et al., 2003; Lee and Choi, 2004; Suzen 

and Doyuran, 2004; Neuhauser and Terhorst, 

2007; Magliulo et al., 2008). Essentially, the 

WofE method is a bivariate statistical technique 

that calculates the spatial probability and odds of 

landslides given a certain variable. 

Many investigations have included 

landslide runout in the analyses for landslide 

hazard assessment. With research on landslide 

runout or travel distance started in mid Nineties 

of the last century (Hungr, 1995; Finlay et al., 

1999; Chen and Lee, 2000; Okura et al., 2000; 

Fannin and Wise, 2001; Wang et al., 2002; Crosta 

et al., 2003; Hunter and Fell, 2003; Bertolo and 

Wieczorek, 2005; Hungr et al., 2005; Malet et 

al., 2005; Crosta et al., 2006; van Asch et al., 

2006; Pirulli et al., 2007; van Asch et al., 2007a; 

van Asch, et al., 2007b) where authors use three 

types of approaches for runout analysis. These are 

the empirical approach from previous landslides 

and geomorphological analysis, the deterministic 

approach from the geotechnical parameters and 

the dynamic approach from numerical modelling 

of runout.


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Landslide vulnerability assessment is a 

fundamental component in the evaluation 

of landslide risk (Leone et al., 1996). Most 

publications about vulnerability are related to 

hazard and risk assessment (Mejia-Navarro et al., 

1994; Leone et al., 1996; Ragozin and Tikhvinsky, 

2000; van Westen, 2002; Hollenstein, 2005). The 

main object of these investigations determined 

the elements of risk which have impact on 

structures on its surface and estimate the cost. 

The vulnerability maps are expressed with values 

between 0 and 1, where 0 means no damage and 

1 means total loss. Generally, the vulnerability 

to landslides may depend on runout distance; 

volume and velocity of sliding; elements at risk 

(buildings and other structures), their nature and 

their proximity to the slide; and the elements 

at risk (person), their proximity to the slide, the 

nature of the building/road that they are in, and 

where they are in the building, on the road, etc 

(Finlay, 1996). 

The aim of landslide hazard and risk 

assessment studies is to protect the population, 

the economy and environment against potential 

damage caused by landslides (Crozier and Glade, 

2005). Risk in this context, is seen as a disaster 

that could happen in the future. The total risk 

map could be obtained by combining hazard and 

vulnerability and made directly or specific risk or 

consequence maps can be created and analyzed 

in order to achieve some preliminary conclusions. 

The classification of the landslide risk assessment 

is still in progress. At the moment the classification 

is based on the level of quantification dividing the 

landslide risk assessment methods in qualitative, 

semi-qualitative and quantitative (AGS, 2000; 

Powell, 2000; Walker 2000; Chowdhury and 

Flentje, 2003). 

The qualitative landslide risk assessment 

approach is based on the experience of the experts 

and the risk areas are categorized generally in 

three or five classes as very high, high, moderate, 

low and very low. This method is applicable for 

spatial analysis using GIS and usually applied at 

national or regional levels. This approach were 

found in literature from Lateltin (1997), AGS 

(2000), Budetta (2004), Cascini (2004), Ko Ko et 

al. (2004), IADB (2005), Nadim et al. (2006). 

With the semi-qualitative landslide 

risk assessment approach, weights are assigned 

under certain criteria, which provide numbers 

as outcome, instead of qualitative classes 

(0-1, 0-10 or 0-100). It could be applicable to 

any scale, but more reasonably used at medium 

scale. Semi-quantitative approach efficiently uses 

spatial multi-criteria techniques implemented in 

GIS that facilitate standardization, weighting and 

data integration in a single set of tools. More 

details about the weighting system are published 

by Brand (1988), Koirala and Watkins (1988), 

Chowdhury and Flentje (2003), Blochl and 

Braun (2005), Castellanos Abella and van Westen 

(2005) and Saldivar-Sail and Einstein (2007). 

When implementing the semi-quantitative 

model, usually the multi-criteria evaluation is 

used (see references below). The input is a set 

of maps that are the spatial representation on 

the criteria, which are grouped, standardised 

and weighted in a criteria tree. Meanwhile the 

output is one or more composite index maps 

indicating the completion of the model used. 

The theoretical background for the multicriteria 

evaluation is based on the Analytical 

Hierarchical Process (AHP) developed by Saaty 

(1977). The AHP has been extensively applied 

on decision making problems (Saaty and Vargas, 

2001). Recently some research has been carried 

out to apply AHP to landslide susceptibility 

assessment (Barredo et al., 2000; Mwasi, 

2001; Nie et al., 2001, Wu and Chen, 2009). 

Komac (2006) designed multivariate statistical 

processing techniques in order to obtain several 

landslide susceptibility models with data at scale 

1:50,000 and 1:100,000. Based on the statistical 

results, several landslides susceptibility maps 

were created. 

Quantitative landslide risk assessment 

has been used for specific slopes or very small 

areas using probabilistic methods or percentage 

of losses expected (Whitman, 1984; Chowdhury, 

1988). Probabilistic values (0-1) are obtained 

at the expense of a certain amount of monetary 

or human loss. Quantitative risk analysis and 

consequent assessment uses information about 

hazard probability, values of elements at risk 

and their vulnerability. Among the quantitative 

approaches found in literature there are some 

basic similarities but also some differences 

between the approaches. They include either 

estimation of hazard or estimation of vulnerability 

and consequences (Morgan, 1992; Einstein, 1988, 

1997; Fell, 1994; Fell et al., 2005; Anderson et al., 

1996; Ragozin, 1996; Ragozin and Tikhvinsky, 

2000; Lee and Jones, 2004; AGS, 2000). 

5. Landslide risk management 

At the end of the assessment process when 

landslide susceptibility and risk assessment 

have been identified, results and measures 

obtained should or may be included into the 

landslide risk management process governed 

by decision makers to mitigate landslide risk of 

the community or, at this level, several further 

approaches are possible. The strategies may 

be grouped into planning control, engineering 

solution, acceptance, and monitoring or warning 

systems. The risk assessed can be compared 

with the acceptance criteria to decide upon the 

landslide mitigation measures required. 

Landslide (or any natural hazard for that matter) 

assessment process is just one of several steps in 

the (Landslide) Risk Management Cycle (RMC), 

which doesn’t end at the stage where results of 

assessment process are included in the RMC. RMC 

is a live system where each measure/provision 

results in a consequence(s) that influence(s) 

further development in and steps of this cycle. In 

a way we could define it as a spiral rather than as 

a circular process since the same position is never 

reached again. 

6. Conclusion 

In this paper, different approaches for the evaluation 

of slope mass processes are reviewed. In general, 

all analyses are based on the assumption that 

historical landslides and their causal relationships 

can be used to predict future ones (“past is a key 

to the future”). However, we can see that many 

researchers use different approaches to evaluate 

landslides, debris flow or rockfall hazard risk 

assessment, which mainly depend on data 

availability. In developing countries, usually the 

lack of financial support to produce risk assessment 

maps for dangerous areas results in emphasis 

on remediation measures. Whereas in countries 

with high standards, the approach to the topic is 

focused into prevention and into remediation if 

disasters occur. In any event the obstacles related 

to the availability of data are smaller each day 

due to low-cost satellite information, the use of 

SRTM, ASTER and Google Earth, which ease the 

creation of landslide inventory databases, a basis 

for any further hazard assessments. The landslide 

inventory map is probably the most important data 

set to work on for producing a reliable prediction 

map of spatial and temporal probability for 

landslides or other slope mass movements and a 

necessity for any type of analyses.


Seite 58 

Seite 59 


Mateja Jemec 

Dimičeva ulica 14 

SI – 1000 Ljubljana, Slovenia 

mateja.jemec@geo-zs.si 

Marko Komac 

Dimičeva ulica 14 

SI – 1000 Ljubljana, Slovenia 

marko.komac@geo-zs.si 


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ROLAND NORER 

Legal Framework for Assessment and Mapping 

of Geological Hazards on the International, 

European and National Levels 

Rechtlicher Rahmen für Analyse und Kartierung 

geologischer Gefahren auf internationaler, 

europäischer und nationaler Ebene 

Summary: 

Legal standards for the assessment and mapping of geological hazards are rather scarce at 

the international and European level. Certain protocols to the Alpine Convention provide for 

the obligation to map geological hazards, but they fail to adopt substantive standards for it. 

At a European level, standards such as those for priority areas are only provided for in drafts 

such as the proposal for a Directive establishing a framework for the protection of soil or are 

mentioned in the Communication on the Community approach to prevent natural disasters. 

At a national level, there are legal provisions in connection with preventive planning on 

natural disasters, although the general problem on the coexistence of multiple area-related 

definitions persists. The extensive exposition of hazards in forestry law remains a central issue. 

The sources and materials encountered to this end are, however, not enough to derivate 

consistent standards and provisions for the assessment and mapping. 


Rechtliche Vorgaben betreffend Analyse und Kartierung geologischer Gefahren sind sowohl 

auf internationaler als auch europäischer Ebene selten. Bestimmte Protokolle zur Alpenkonvention 

sehen Kartierungspflichten für geologische Risiken vor, ohne allerdings materielle 

Vorgaben zu treffen. Im Europarecht finden sich solche Regeln lediglich in Entwürfen wie bei 

den prioritären Gebieten im Vorschlag einer EU-Bodenrahmenrichtlinie oder sie werden wie 

im Gemeinschaftskonzept zur Verhütung von Naturkatastrophen erst in Aussicht gestellt. 

Auf nationaler Ebene bestehen in der Regel Rechtsvorschriften im Zusammenhang mit 

präventiven Planungen bei Naturgefahren, wenngleich das allgemeine Problem des Nebeneinanders 

von mehreren gebietsbezogenen Festlegungen besteht. Als zentrale Vorschriften 

gelten die flächenhaften Gefahrendarstellungen im Forstrecht. Das vorgefundene Material 

reicht jedenfalls nicht aus, um einheitliche Standards und Vorgaben für Analyse und Kartierung 

ableiten zu können. 

1. Introduction 

A glance at the legal framework on assessment 

and mapping of geological hazards 1 is difficult. 

No coherent legal system on the 

management of natural disasters can be found at 

either the international or European level. Also, a 

legal fragmentation can be detected at a national 

level. Therefore, the art is to filter something like 

a legal essence out of diverse dispersed norms, 

which are often only partly related to this topic 

and follow different legal approaches. 2 This will 

be the attempt in the following sections. Naturally, 

the essay will not exceed a more or less abundant 

outline of the issue. 

2. International law 

2.1. Alpine Convention 

The Alpine Convention 3 and its protocols 

are the only source of international law. The 

“Soil Conservation Protocol” 4 provides for the 

obligation to draw up maps of Alpine areas “which 

are endangered by geological, hydrogeological 

and hydrological risks, in particular by land 

movement (mass slides, mudslides, landslides), 

avalanches and floods”, and to register those areas 

and to designate danger zones when necessary 

(art. 10.1). 

Likewise, areas damaged by erosion and 

land movement shall be rehabilitated in as far 

as this is necessary for the protection of human 

beings and material goods (art. 11.2). 

1 

For the “Natural hazards profile“ of landslips, rock fall, avalanches 

and landslides, see RUDOLF-MIKLAU, Naturgefahren- 

Management in Österreich (2009), p. 21 et seq. 

2 

For an overview regarding norms of prevention, see RUDOLF- 

MIKLAU (fn. 1), p. 97 et seq. 

3 

BGBl. 1995/477. 

4 

BGBl. III 2002/235. 

Both provisions were classified as binding and 

directly applicable. 5 

In addition, the “Mountain Forests 

Protocol” 6 aims to preserve and, whenever 

necessary, to develop or increase mountain forests 

as a near-natural habitat (art. 1.1) and imposes the 

duty of the Contracting Parties to give priority to the 

protective function of mountain forests (art. 6.1). 

The “Spatial Planning and Sustainable 

Development Protocol“ 7 establishes the obligation 

to determine the areas subject to natural hazards, 

where building of structures and installations 

should be avoided as much as possible (art. 

9.2.e). The spatial planning policies also take 

into account the protection of the environment, 

in particular with regard to the protection against 

natural hazards (art. 3.f). 

2.2. Findings 

In international law, only certain provisions 

established in the protocols to the Alpine 

Convention refer to the obligation to map 

geological hazards. But farther-reaching, 

additional substantive elaborations arising out of 

these duties are not revealed before the respective 

national implementation measures. 

3. European law 

3.1. Soil protection law 

The communication from the European 

Commission in 2002 about a Strategy for Soil 

Protection 8 aims at the further development of 

5 

BMLFUW (ed.), Die Alpenkonvention: Handbuch für ihre 

Umsetzung (2007), p. 112. Implementation analysis by 

SCHMID, Das Natur- und Bodenschutzrecht der Alpenkonvention. 

Anwendungsmöglichkeiten und Beispiele, in: CIPRA 

Österreich (ed.), Die Alpenkonvention und ihre rechtliche 

Umsetzung in Österreich – Stand 2009, Tagungsband der 

Jahrestagung von CIPRA Österreich, 21.-22.Oktober 2009, 

Salzburg (2010), p. 33 et seq. 

6 

BGBl. III 2002/233. 

7 

BGBl. III 2002/232..


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Seite 67 

political commitment to soil protection in order 

to achieve a more comprehensive and systematic 

protection. As soil formation is an extremely slow 

process, soil can essentially be considered as a 

non-renewable resource. 9 It proceeds to mention 

eight main threats to soil in the EU 10 , including 

“erosion” and “floods and landslides”. These are 

intimately related to soil and land management. 

“Floods and mass movements of soil cause 

erosion, pollution with sediments and loss of soil 

resources with major impacts for human activities 

and human lives, damage to buildings and 

infrastructures, and loss of agricultural land”. 11 

In 2006, the European Commission followed 

suit with a Thematic Strategy for Soil Protection 12 

and with a Proposal for a Directive establishing 

a framework for the protection of soil 13 , the latter 

of which provides in its art. 6 for priority areas 

(first draft: risk areas) with regard to landslides. 

The addendum landslides “brought about by the 

down-slope, moderately rapid to rapid movement 

of masses of soil and rock material” fell victim to 

the changes made by the European Parliament. 14 

Also, a programme of measures shall be adopted 

within five years of the implementation of the 

Directive (art. 8). A list of common elements for 

the identification of areas at risk of landslides can 

be found in the appendix. 15 

8 

Communication from the Commission to the Council, the 

European Parliament, the Economic and Social Committee and 

the Committee of the Regions – Towards a Thematic Strategy 

for Soil Protection, COM(2002) 179 final. 

9 

Communication from the Commission to the Council, the 

European Parliament, the Economic and Social Committee 

and the Committee of the Regions – Thematic Strategy for Soil 

Protection, COM(2006) 231 final, Section 1. 

10 

Towards a Thematic Strategy for Soil Protection (fn. 8), 

Section 3. 

11 

Towards a Thematic Strategy for Soil Protection (fn. 8), 

Section 3.8. 

12 

Thematic Strategy for Soil Protection (fn. 9). 

13 

Proposal for a Directive of the European Parliament and of 

the Council establishing a Framework for the Protection of Soil 

and amending Directive 2004/35/EC, COM(2006) 232 final.2.. 

14 

European Parliament legislative resolution of 14 November 

2007 on the proposal for a directive of the European 

Parliament and of the Council establishing a framework for 

the protection of soil and amending Directive 2004/35/EC, 

P6_TA(2007)0509. 

15 

Annex I Section 5: soil typological unit (soil type), properties, 

occurrence and density of landslides, bedrock, topography, 

land cover, land use (including land management, farming 

systems and forestry), climate and seismic risk. 

In particular, the EU Directive establishing a 

Framework for the Protection of Soil turned out 

to be fiercely disputed. 16 Since 2007, after an 

attenuated version failed to obtain the majority 

in the EU Environment Council, the future of this 

proposal remains uncertain. 

3.2. Environmental law 

In the remaining European environmental laws, 

certain provisions about erosion can be found. 17 

However, there are no further provisions dealing 

with the topic of this essay. 

3.3. Agricultural law 

The situation is rather similar in the area of 

European agricultural law. Different standards 

are included in the general provisions on direct 

payments (cross compliance) 18 , in which there is 

an obligation to maintain all agricultural land in 

good agricultural and environmental condition, 

such as those regarding soil erosion. 19 In contrast, 

the regulation on support for rural development 20 

includes in its Axis 2 some links with supporting 

measures, such as afforestation (cf. art. 50.6). 21 

16 

Cf. in detail NORER, Bodenschutzrecht im Kontext der europäischen 

Bodenschutzstrategie (2009), p. 17 et seq. 

17 

Like the Directive 2000/60/EC establishing a framework for 

Community action in the field of water policy (“Wasserrahmenrichtlinie“), 

OJ 2000 L 327/1. 

18 

Art. 4 et seq. Council Regulation (EC) No. 73/2009 establishing 

common rules for direct support schemes for farmers 

under the common agricultural policy and establishing certain 

support schemes for farmers, OJ 2009 L 30/16. 

19 

Art. 6 in conjunction with Annex III Regulation (EC) 73/2009; 

§ 5.1 in conjunction with Annex INVEKOS-CC-V 2010, BGBl. II 

2009/492. 

20 

Council Regulation (EC) No. 1698/2005 on support for rural 

development by the European Agricultural Fund for Rural Development 

(EAFRD), OJ 2005 L 277/1. 

21 

Cf. Recital 32, 38, 41 and 44 Regulation (EC) 1698/2005. For 

Austrian implementation see Sonderrichtlinie zur Umsetzung 

der forstlichen und wasserbaulichen Maßnahmen im Rahmen 

des Österreichischen Programms für die Entwicklung des 

ländlichen Raums 2007 – 2013 „Wald & Wasser“, BMLFUW- 

LE.3.2.8/0054-IV/3/2007 idF BMLFUW-LE.3.2.8/0028- 

IV/3/2009. 

3.4. Spatial planning law 

Regarding the quantitative aspects of soil 

protection, a separate communication on the 

topic of “Planning and Environment – the 

Territorial Dimension” has been announced for a 

some time now. This communication should deal 

with rational land-use planning, as addressed by 

the Sixth Environment Action Programme. 22 The 

announced content, however, does not refer to a 

special relevance for the prevention of landslides. 

Hence, at present the only object of an integrated 

and sustainable management at the EU level is 

the flood prevention programme in transnational 

river areas included in the European Spatial 

Development Perspective (ESDP). 23 

3.5. Disaster law 

The Communication of the European Commission 

of February 2009 24 was another attempt to 

establish measures, based on the already existing 

instruments, for a Community approach on the 

prevention of natural and man-made disasters. 

Three key elements were mentioned for 

the Community approach: creating the conditions 

for the development of knowledge based disaster 

prevention policies at all levels of government, 

linking the actors and policies throughout the 

disaster management cycle and making existing 

instruments perform better for disaster prevention. 

In particular, the subsection “Developing 

guidelines on hazard/risk mapping” (3.1.3) is 

of great interest. Here, the Commission tries 

22 

Towards a Thematic Strategy for Soil Protection (fn. 8), Section 

2.1, 6.1.; REISCHAUER, Bodenschutzrecht, in: Norer (ed.), 

Handbuch des Agrarrechts (2005), p. 491. 

23 

European Commission (ed.), ESDP European Spatial 

Development Perspective. Towards Balanced and Sustainable 

Development of the Territory of the European Union (1999), 

Section 146. 

24 

Communication from the Commission to the European 

Parliament, the Council, the European Economic ad Social 

Committee and the Committee of the Regions. A Community 

approach on the prevention of natural and man-made disasters, 

COM(2009) 82 final, 23.02.2009. 

to collect and unify information about hazard/ 

risks by developing Community guidelines for 

hazard and risk mapping, building upon existing 

Community initiatives. However, these should 

focus on disasters with potential cross-border 

impact, exceptional events, large-scale disasters, 

and disasters for which the cost of recovery 

measures appears to be disproportionate when 

compared to that of preventive measures. Also, a 

more efficient targeting of Community funding 25 

is dealt with (3.3.1) by establishing an inventory 

of existing Community instruments capable 

of supporting disaster prevention activities, as 

well as by developing a catalogue of prevention 

measures (e.g. measures integrating preventive 

action in reforestation/afforestation projects). 

Furthermore, a Council Decision 

establishing a Community Civil Protection 

Mechanism 25 deals with assistance intervention 

in the event of major emergencies, or the 

imminent threat thereof. However, a regulation 

on geological mass movements similar to the EU 

Directive on the assessment and management of 

flood risks 27 , with its flood hazard maps and flood 

risk maps, does not currently exist. 

3.6. Findings 

Some relevant regulations can be found at the 

European level. However, only one of them, Cross 

Compliance, is in force and affects the topic dealt 

with in this essay in a rather marginal way. By 

contrast, the Proposal for a Directive establishing 

a Framework for the Protection of Soil, which has 

been put on hold, contemplates the designation 

of landslide risk areas and the establishment of 

25 

Especially the European Agricultural Fund for Rural Development, 

the Civil Protection Financial Instrument, LIFE+, 

the ICT Policy Support Programme, the Research Framework 

Programme. 

26 

Council Decision 2007/779/EC of 8 November 2007, OJ 

2007 L 314/9. 

27 

Directive 2007/60/EC on the assessment and management of 

flood risks, OJ 2007 L 288/27.


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Seite 69 

action programmes. Furthermore, a Community 

approach on the prevention of natural disasters 

sets out guidelines for the unification of hazard 

mapping in large-scale disasters. 

4. National law 

4.1. Forestry law 

Many times, the catchment area of mountain 

torrents and avalanches, as well as references to 

rock fall and landslip areas, are established within 

the national forestal spatial planning. 28 It can even 

include the layout of forests with a protective 

function 29 or the extensive hazard description 

structured in risk levels. 30 The protective effect of 

the forest especially implies “the protection against 

natural peril and contaminating environmental 

influences as well as the conservation of the soil 

against torrents and drift, boulders accumulation 

and landslides”. 31 Thus, forests with a direct 

protective function against the above-mentioned 

hazards could be signalised by means of an 

administrative act (Bannwälder). 32 

4.2. Water law 

Such regulations are limited to measures for flood 

prevention 33 , although geological risks are at 

times also included 34 . 

28 

In Austria e.g. the mapping of risk areas is based on § 11 Austrian 

Forestry Act 1975, BGBl. 1975/440, in conjunction with § 

7.a Regulation on the mapping of risk areas, BGBl. 1976/436, 

including brown areas of reference, which posed other hazards 

than mountain torrents and avalanches, such as rock fall 

and landslips. Cf. JÄGER, Raumwirkungen des Forstrechts, 

in: Hauer/Nußbaumer (ed.), Österreichisches Raum- und 

Fachplanungsrecht (2006), p. 181 et seq.; STÖTTER/FUCHS, 

Umgang mit Naturgefahren – Status quo und und zukünftige 

Anforderungen, in: Fuchs/Khakzadeh/Weber (ed.), Recht im 

Naturgefahrenmanagement (2006), p. 21 et seq. 

29 

In Austria e.g. Forestry Development Plan (Waldentwicklungsplan) 

based on § 9 Austrian Forestry Act 1975. 

30 

In Austria e.g. hazard and risks mapping (Gefahren- und 

Risikokarten), here geological hazard mapping (no legal basis). 

31 

Such as in § 6.2b Austrian Forestry Act 1975. 

32 

Such as in § 27.2.a Austrian Forestry Act 1975. 

33 

In Austria e.g. Section 4 of the Water Law Act 1959, BGBl. 

1959/215 (Wv). 

4.3. Soil protection law 

The rules on soil protection can be divided in two 

categories with different aims: on the one hand, 

qualitative soil damage such as contaminating 

activities and structural damages and on the 

other hand, quantitative soil loss, such as soil 

degradation and erosion. 35 The second category 

could also be of interest for mass movements. 36 

4.4. Spatial planning law 

As a general rule, rules on areas with a higher 

risk of mass movements in connection with the 

designation of building sites 37 or special use in 

grassland can be mainly found in spatial planning 

law. Further contents in this regard remain 

missing. 38 

4.5. Building law 

A similar situation applies to building law. The 

suitability as a building site for areas with a higher 

risk of mass movements is not given. 39 

34 

In Austria e.g. Water Construction Development Act (Wasserbautenförderungsgesetz), 

BGBl. 1985/148 (Wv), expressly 

mentions the necessary protection against “rock fall, mudflow 

and landslides” in the requirements for granting and allocation 

of federal funds to pursuit the objectives in the Act (§ 1.1.1.b). 

35 

Cf. HOLZER/REISCHAUER, Agrarumweltrecht. Kritische 

Analyse des „Grünen Rechts“ in Österreich (1991), p. 47; 

REISCHAUER (fn. 22), p. 477. 

36 

In Austria e.g. the pertinent national provisions only provide 

for land-use measures for soil in erosion areas; see § 5 Burgenland 

Soil Protection Act (Burgenländisches Bodenschutzgesetz), 

LGBl. 1990/87; § 27 Upper Austria Soil Protection 

Act 1991 (Oberösterreichisches Bodenschutzgesetz), LGBl. 

1997/63; § 7 Salzburg Soil Protection Act (Salzburger Bodenschutzgesetz), 

LGBl. 2001/80; § 6 Styria Agricultural Soil 

Protection Act (Steiermärkisches landwirtschaftliches Bodenschutzgesetz), 

LGBl. 1987/66. 

37 

In Austria e.g. § 37.1.a Tyrol Spatial Planning Act (Tiroler 

Raumordnungsgesetz), LGBl. 2006/27, according to which 

certain areas are excluded as building sites when f.i. there is a 

risk of „rockfall, landslide or other gravitated natural hazards”. 

From the perspective of avalanche protection see in detail 

KHAKZADEH, Rechtsfragen des Lawinenschutzes (2004), p. 

37 et seq. 

38 

F.i. the Recommendation Nr. 52 of the Austrian Spatial Planning 

Conference (ÖROK) about preventive handling with natural 

hazards in Spatial Planning (2005) also puts an emphasis 

in floods. Cf. for Austria altogether KANONIER, Raumplanungsrechtliche 

Regelungen als Teil des Naturgefahrenmanagements, 

in: Fuchs/Khakzadeh/Weber (ed.), Recht im Naturgefahrenmanagement 

(2006), p. 123 et seq. 

4.6. Findings 

In the light of the arid gain at the international and 

European legal level, at a first glance the respective 

national systems seem to constitute the determining 

factor, by implementing higher-ranking guidelines 

or autonomously. However, norms related to the 

assessment and mapping of geological hazards, 

such as the law of natural disaster management 

at all 40 , remain fragmentated between the various 

regulations (“Querschnittsmaterien”). Relevant 

provisions exist, primarily in forestry law with its 

extensive hazard descriptions, but also marginally 

in spatial planning law. This fact, however, would 

not allow the development of uniform standards 

and provisions for assessment and mapping of 

geological hazards. 41 

5. Conclusion 

Legal provisions regarding the assessment and 

mapping of geological hazards are tenuously 

sown at the international and European level. 

Unlikely enough, at the national level more legal 

provisions exist in connection with preventive 

planning 42 for natural hazards. Here, the existing 

instruments partially conduct the assessment of 

mass movements, although the general problem 

of the coexistence of different area-related 

definitions still remains. 43 

39 

In Austria e.g. § 5.1.5 Styria Building Act (Steiermärkisches 

Baugesetz), LGBl. 1995/59, according to which a plot area is 

only suitable for building if the risks posed by „flood debris 

accumulation, rockfall, landslides” are not to be expected. From 

the perspective of avalanche protection see in detail KHAKZ- 

ADEH (fn. 37), p. 58 et seq. 

40 

For Austria see e.g. HATTENBERGER, Naturgefahren und 

öffentliches Recht, in: Fuchs/Khakzadeh/Weber (ed.), Recht im 

Naturgefahrenmanagement (2006), p. 67 ; RUDOLF-MIKLAU 

(fn. 1), p. 57 and list 61 et seq., speaking of „Kompetenzlawine“. 

41 

WEBER/OBERMEIER, Verwaltungs- und zivilrechtliche Aspekte 

von Steinschlaggefährdung und –schutz, Studie im Auftrag 

des Bundesministeriums für Land- und Forstwirtschaft, Umwelt 

und Wasserwirtschaft (2008, unveröffentlicht), p. 29, suggest 

for Austria f.i. an extension of the competence „Wildbach- und 

Lawinenverbauung“ towards other natural hazards. The political 

feasibility seems little realistic. 

42 

For Austria see in detail RUDOLF-MIKLAU (fn. 1), p. 129 et 

seq.; HATTENBERGER (fn. 40), p. 73 et seq. 

43 

For Austria see HATTENBERGER (fn. 40), p. 84 et seq. 

A convincing and coherent overall view cannot 

be offered. Whereas the available legal set of tools 

remains within the same course of action, no 

relevant changes coming from the international 

and European level are to be expected in the 

near future. Admittedly, the creation of uniform 

technical standards by all those involved as a 

further step towards self-regulation should be 

brought to mind. 


Univ.-Prof. Dr. Roland Norer 

University of Lucerne 

School of Law 

Hofstraße 9 

P.O. Box 7464 

CH-6000 Luzern 7 

Switzerland


Seite 70 

Seite 71 

KARL MAYER, BERNHARD LOCHNER 

Internationally Harmonized Terminology 

for Geological Risk: Glossary (Overview) 


Ausgangslage und Motivation für dieses Projekt ist die schon „traditionelle“ Problematik der 

unterschiedlichen Verwendung und Definition der Begrifflichkeiten in der Fachliteratur zum 

Themenbereich Massenbewegungsprozesse. Dies hat zur Folge, dass die Arbeitsweisen der 

Experten in den verschiedenen geologischen Ämtern in den Projektpartnerländern nicht einheitlich 

sind und es daher immer wieder zu Missverständnissen und Schwierigkeiten bei der 

Abstimmung gemeinsamer Projekte kommt. Aufgrund dieser Komplexität und der Unklarheit, 

die speziell im deutschsprachigen Raum, aber auch europaweit, besonders im Hinblick auf 

die Klassifikation der Massenbewegungen existiert, soll ein mehrsprachiges Glossar erstellt 

werden, in welchem im Sinne der internationalen Harmonisierung in Absprache mit den 

einzelnen Projektpartnerländern die von den jeweiligen geologischen Ämtern verwendeten 

administrativen Begriffe eingestellt und in Beziehung gesetzt werden. Das gesamte Projekt 

gliedert sich grundsätzlich in einen technischen und einen inhaltlichen Teil, wobei die erste 

Projektphase vom technischen Bereich bestimmt wird. Da die harmonisierten Begrifflichkeiten 

und Definitionen für alle beteiligten Länder und auch für eine breitere Öffentlichkeit zugänglich 

gemacht werden soll, wird eine relationale Datenbank erstellt, in welcher die Inhalte 

logisch verknüpft werden und welche zu Projektende in die LfU-Homepage integriert wird. 

Internationale Harmonisierung der Fachterminologie 

für geologische Risiken: Glossar (Überblick) 

Summary: 

Purpose and motivation for this project are the difficulties traditionally encountered when 

using or defining mass movements terms in scientific papers. This results in different methods 

and concepts being used by geological agencies and finally leads to misunderstandings 

and problems in cooperative international projects. In order to tackle that complexity and 

ambiguity, found not only in the German-speaking geology, but generally throughout Europe, 

a multilingual glossary shall be created. This glossary aims at an international harmonization 

by providing the user with a selection of official terms used by the geological agencies in a 

specific country and by setting relations to similar terms employed in other countries. The 

resulting harmonized terms and definitions should be made available to all partners and to the 

general public on the internet through the Bavarian Environment Agency homepage. The first 

step is to design and implement the technical infrastructure required to store and query the 

terms. For this purpose, a relational database management system will be used as a back-end. 

1. Requirements for the relational database 

Before the actual database is deigned, it is essential 

to assess the exact requirements for the glossary. 

This eases the following conceptional work a lot 

and minimizes time-consuming adjustments and 

changes to the model later on. 

First a list of attributes needed for a single 

glossary term as well as a type for those attributes 

(e.g. numbers, text, keys etc.) is to be defined. 

The type of attribute determines which relations 

can be saved in the database and what kind of 

information can be queried using them. Every 

attribute corresponds at least to one column in the 

main glossary table. 

The unique language to which a 

term is assigned is a fundamental attribute in 

a multilingual glossary. Because of the pan- 

European character of the glossary, it is necessary 

to specify the languages more precisely by linking 

them to a specific country, resulting in a unique 

combination for one language and one country. 

It is particularly relevant for this project, as the 

usage of a term varies greatly within a language 

depending on the region where it is used, as 

it is the case for German (Germany, Austria, 

Switzerland). 

Easy and intuitive queries are essential 

for the usability of the glossary. Although the 

user friendliness mostly depends on the graphical 

user interface and is hard to control through the 

database design, there are still aspects that need 

to be considered in conception. It is important to 

determine what possible queries will be offered 

to the user (e.g. a search by synonyms, case and 

special character insensitive searches, etc.) and to 

adapt the database design accordingly. 

Editing and adding glossary terms after 

the initial import should also be possible and 

requires saving metadata for each entry, e.g. time 

and date of the creation or the last edit of a term. 

Using that information, it is easy to reconstruct the 

history of an entry at a later point in time.


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PK 

Finally, the database should, to some 

extent, be expandable if future needs for 

extensions or additional functions arise. 

1.1 Relations 

tdtaTerm 

idterm 

idworkflowstatus 

metacreator 

metaowner 

idreadaccess 

idwriteaccess 

deleted 

metamasterlang 

metalastedit 

The classical approach followed by most 

glossaries is a single translation layer; a direct 

translation of each term into exactly one term 

of another language. This corresponds to a 1: n 

relation between the entities (i.e. glossary terms) 

in an entity-relationship model (ERM). Such a 

direct translation supposes an equivalence of 

the terms’ definition and meaning. In this new 

glossary, the relations between the different 

terms should be defined solely by their technical 

meaning, resulting in two possible relations: same 

meaning or similar meaning. A direct translation is 

still required in order to provide the user with the 

exact translation of a definition in his language. 

Following example should help clarifying 

the concept of “meaning” vs. “definition”: 

The English term “rock fall” is usually 

translated into “Felssturz” or “Bergsturz” in 

German, but that translation usually doesn't 

consider the effective volume transported. 

However, if the technical meaning is taken into 

account, “Bergsturz”, which corresponds to a 

minimum volume of 106 cubic meters, would 

have the same meaning as “rock avalanche”, also 

characterized by volume values above 106 cubic 

tdtaTermLng 

PK, FK1 

PK 

meters. The relation to “rock fall” (i.e. similar 

meaning) would be a looser one. The relations 

between “cliff falls“, “block falls“, “boulder falls“ 

and “Felssturz“, “Steinschlag“, “Blockschlag“ 

could be defined in a similar manner. 

(Note: the values used above are examples and do 

not necessarily match any official values) 

1.2 Database model 

This chapter describes in detail the different 

“sections” of the database. For the purpose 

of clarity, the database was divided into four 

“sections” or “areas” which correspond to a set of 

interrelated tables. The following diagram shows 

the relations between those “sections”. 

Glossary 

• Terms 

• Relations 

• Translation tables 

Metadata 

• Workflow 

• History 

idterm lang 

term description 

Fig. 1: Example of a multilingual glossary where each term has exactly one translation in 

each other language. The primary key of the language table ('tdtaTermLng') is defined by 

its ID and language 

Abb. 1: Beispiel eines mehrsprachigen Glossars, in dem jeder Begriff genau eine 

Übersetzung für jede weitere Sprache hat. Der Primärschlüssel der Tabelle mit dem 

Textinhalt ('tdtaTermLng') ist somit über ID und Sprache definiert. 

Auxiliary 

• Key tables 

• Relation tables 

User Management 

• Users & groups 

• Permissions 

Fig. 2: Overview of the database model components 

Abb. 2: Übersicht über die Komponenten des Datenbankmodells 

The nomenclature used throughout the database 

follows a simple naming convention. Depending 

on the function or content of a particular table, 

its name is prefixed differently. The prefix “tdta-” 

stands for tables in which actual data is being stored, 

“tkey-” is used for key tables (key attributes can 

only take a value from a predefined set of keys) and 

“trel-” for relation tables. Unique IDs are prefixed 

with “id-” and meta-attributes with “meta-”. 

For most of the tables the multilingual concept 

required by the direct translation provides a 

second table with an identical name and the suffix 

“-Lng”. Those language tables hold the text values 

of the different glossary terms. The first “section” 

is the core of the database, with its element tables 

tdtaElement and tdtaEleGlossarTerm. The glossary 

terms are stored in the latter, whereas the main 

element table holds additional information related 

to the system and not to the glossary itself (mostly 

through the usage of foreign keys). 

tdtaEleGlossarTerm 

PK,FK1 idelement 

FK3 

FK4 

FK2 

term 

reference 

idtopic 

idlang 

idcountry 

searchterm 

searchsynonyms 

Fig. 4: Auxiliary tables 

Abb. 4: Behelfstabellen 

tkeyCountry 

PK idcountry 

countrysort 

PK 

tkeyLang 

idlang 

langsort 

tkeyTopic 

PK idtopic 

topicsort 

PK 

FK4 

FK2 

FK1 

FK5 

FK3 

PK,FK1, 

PK,FK2 

tdtaElement 

idelement 

elementtype 


metaowner 

metacreator 

idreadaccess 

idwriteaccess 

deleted 


tdtaElementLng 

idelement 

lang 

tdtaEleGlossarTermLng 

PK,FK1 

PK,FK2 

PK,FK1 

PK,FK2 

PK,FK1 

PK,FK2 

idcountry 

lang 

title 

summary 

metacreated 

metalastedit 

metatranslator 

countryterm 

tkeyLangLng 

idcountry 

lang 

langterm 

idlanguage 

tkeyTopicLng 

idtopic 

lang 

topicterm 

PK 

PK,FK1 

FK3 

FK4 

FK2 


idelement 

term 

reference 

idtopic 

idlang 

idcountry 

searchterm 

searchsynonyms 

tdtaEleGlossarTermLng 

PK,FK1, FK2 

PK,FK1 

Fig. 3: Main tables 

Abb. 3: Haupttabellen 

PK,FK1 

PK 

tkeyLanguage 

idlanguage 

lang 

languagesort 

tkeyLanguageLng 

idlanguage 

lang 

languagesort 

idelement 

lang 

title 

description


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Seite 75 

For each term, following fields are available: 

• 'term': the actual text value (direct 

translation using the -Lng table) 

• ‘reference’: source of information and date 

• 'idlang' and 'idcountry': foreign keys 

pointing to a unique combination of 

language/country 

• 'idtopic': foreign key specifying the topic of 

this term 

• 'searchterm' and 'searchsynonyms': used 

for insensitive searches 

• 'picture': paths to pictures depicting a term 

PK 

PK 

FK4 

FK2 

FK1 

FK5 

FK3 

PK 

FK1 

tkeyWorkflowStatus 


workflowstatussort 

tdtaElement 

idelement 

elementtype 


metaowner 

metacreator 

idreadaccess 

idwriteaccess 

deleted 


tdtaUser 

iduser 

username 

password 

email 

organisation 

fullname 

inactive 

superadmin 

lastlogin 

loginip 

maingroup 

Fig. 5: Metadata tables 

Fig. 5: Metadata tables 

The auxiliary tables are mainly key tables defining 

the different languages, countries and topics used 

in the main table. They also contain the relation 

table used to specify relations between terms 

based on a relation code (“similar” or “same”). 

Metadata is partly stored in the tdtaElement table 

using foreign keys. Those keys point to external 

metadata tables such as tkeyWorkflowstatus 

or tdtaUser, where, for example, information 

about the status, author or owner of an element 

are defined. tdtaHistory works similarly to a log 

by saving all actions performed on a specific 

tkeyWorkflowStatusLng 

PK,FK1 

PK,FK2 

PK,FK1 

FK3 

FK4 

FK2 

PK 

FK2 

FK1 


lang 

workflowstatusterm 


idelement 

term 

reference 

idtopic 

idlang 

idcountry 

searchterm 

seyrchsynonyms 

tdtaHistory 

idhistory 

idelement 

lang 

iduser 

logdatetime 

info 

idelementaction 

PK,FK1 

PK 

FK2 

PK 

tkeyLanguage 

idlanguage 

lang 

languagesort 

tkeyLanguageLng 

PK,FK1 

PK 

idlanguage 

lang 

languagesort 

tkeyelementActionLng 

PK 

FK1 


lang 

elementactionterm 

idlanguage 

tkeyElementAction 


elementactionsort 

idhistory 

PK 

FK4 

FK2 

FK1 

FK5 

FK3 

PK 

FK1 

tdtaElement 

idelement 

elementtype 


metaowner 

metacreator 

idreadaccess 

idwriteaccess 

deleted 


tdtaUser 

iduser 

username 

password 

email 

organisation 

fullname 

inactive 

superadmin 

lastlogin 

loginip 

maingroup 

element, which can be displayed as a list to an 

authorized user. 

Finally, user and group management 

defines the group(s) a user belongs to and which 

read/write rights a group or a specific user owns 

(through the tdtaElement table) 

1.3 Data capture and import 

PK 

PK,FK2 

PK,FK1 

Fig. 6: User and group management 

Abb. 6: Benutzer- und Gruppenverwaltung 

The primary data capture is done via an Excel 

table with a predefined format. This table is used 

as an interface to import data records in the 

database. The person responsible for filling out 

this table must ensure that the relations between 

the terms are set correctly. Other errors, such as 

tdtaGroup 

idgroup 

groupname 

description 

trelUserGroup 

iduser 

idgroup 

PK 

duplicate IDs, can be handled to some extent by 

the database itself. The integration of the database 

into the homepage from the Bavarian Environment 

Agency (LfU) and a graphical user interface to 

manually add or edit single terms is planned in 

the final stage of the project. 

2. Contents of the glossary 

tkeyPermissionLevelLng 

PK,FK1 

PK 

tkeyPermissionLevel 

idpermissionlevel 

permissionlevelsort 

idpermissionlevel 

lang 

permissionlevelterm 

In view of a different use of landslide-terms in the 

European countries, a multilingual glossary can help 

to improve the collaboration between the experts. 

Also, progress concerning the comparability of the 

methods dealing with geological hazards in the 

several countries is to be achieved.


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In general, the glossary implies terms and 

definitions to landslides and corresponding maps, 

considering “danger, hazard and risk” caused by 

several kinds of geological hazards. Due to the 

“alpine – character” of the project, the glossary 

contains all the languages spoken in the Alpine 

region plus English and Spanish for two additional 

European countries dealing with geological 

hazards. Therefore, the glossary consists of the 

following six languages: 

• German – Germany, Switzerland, Austria 

(three different lists) 

• Italian – Italy 

• French – France 

• Slovenian – Slovenia 

• Spanish – Spain (Castilian and Catalan) 

• English – United Kingdom 

2.1 Basic list for Germany 

For the development of such a glossary, it is 

necessary to create a “basic list” in which all 

the desired terms and definitions are included. 

Therefore a table with 92 terms and definitions 

for geological hazards (in German) was drafted. 

Based on this, the other language lists were 

developed. More information on the approach of 

this “Harmonization” is available in chapter 3.2. 

In order to facilitate this process, all 

the terms are structured in different topics. 

This classification is very useful for simplifying 

the comparability between the languages. For 

example, it’s much easier to get the English term 

for “Stauchwulst” if the English expert knows that 

you are searching for an accumulation term. This 

topical limitation helps the translator to get the 

several experts on the right track. 

The “basic list” is structured into the 

following topics: 

• Accumulation (Ablagerungen - z.B. 

Schuttkegel) 

• General geomorphology (Allgemeine 

Geomorphologie - z.B. Grat) 

• General (Allgemeines - z.B. 

Primärereignis) 

• Fracture forms (Anbruchformen - z.B. 

Bergzerreissung) 

• Path of movement (Bewegungsbahnen - 

z.B. Sturzbahn) 

• Flow process slow (Fließprozess – langsam 

- z.B. Solifluktion) 

• Flow process rapid (Fließprozess – schnell 

- z.B. Blockstrom) 

• Flow process very rapid (Fließprozess – 

sehr schnell - z.B. Murgang) 

• Risk (Gefahr-Gefährdung-Risiko - z.B. 

Restrisiko) 

• Maps (Karten - z.B. Gefahrenkarte) 

• Classification – processes (Klassifikation – 

Prozesse - z.B. Sturzprozess) 

• Measures (Maßnahmen - z.B. aktive 

Maßnahmen) 

• Slides combined (Rutschprozess – 

Kombinierte Rutschung - z.B. Rutschung 

mit kombinierter Gleitfläche) 

• Slides rotational (Rutschprozess 

– Rotationsrutschung - z.B. 

Rotationsrutschung) 

• Slides translational (Rutschprozess 

– Translationsrutschung - z.B. 

Translationsrutschung) 

• Landslide dynamics (Rutschungsdynamik - 

z.B. aktuelle Hangbewegung) 

• Landslide features (Rutschungsmerkmale - 

z.B. Rutschungkopf) 

• Falls (Sturzprozess – Bergsturz - z.B. 

Bergsturz) 

• Falls (Sturzprozess – Blockschlag - z.B. 

Blockschlag) 

• Falls (Sturzprozess – Felssturz - z.B. 

Felssturz) 

• Falls (Sturzprozess – Steinschlag - z.B. 

Steinschlag) 

• Subrosion (Subrosionsprozess - z.B. 

Doline) 

As mentioned above, the different terms lists 

will be integrated in the official homepage of 

the Bavarian Environment Agency in a final step. 

Therefore, the terms are collected in a predefined 

id term lang country definition reference topic 

2016 Abflusslose 

Senke 

2066 aktive 

Maßnahmen 

2070 Aktuelle 

Hangbewegung 

de 

de 

de 

DE 

DE 

DE 

2029 Anbruch de DE 

2027 Auslöser de DE 

2092 Bachschwinde 

(Ponor) 

de 

DE 

2079 Bergsturz de DE 

Fig. 7: Extract of the “Basic-Terms-Table” in German 

Abb. 7: Auszug aus der Deutschen Begriffstabelle 

Senke ohne natürlich möglichen 

oberirdischen Wasserabfluss. In 

einem fluviatil geprägten Relief 

stellt sie eine Anomalie dar, die 

u.U ein Hinweis auf Hangbewegungen 

sein kann 

Schutzmaßnahme, die dem Naturereignis 

aktiv entgegenwirkt, 

um die Gefahr zu verringern 

oder um den Ablauf eines Ereignisses 

oder dessen Eintretenswahrscheinlichkeit 

wesentlich zu 

verändern. Neben den klassischen, 

punktuellen technischen 

Schutzmaßnahmen wie zum 

Beispiel Stützmauer oder Felsanker 

sind auch flächendeckende 

Maßnahmen im Einzugsgebiet, 

beispielsweise Aufforstungen 

oder Entwässerungen, dieser 

Kategorie zuzuordnen. 

Hangbewegung die zum Zeitpunkt 

der Aufnahme aktiv oder 

bezüglich ihres Alters für die 

Untersuchungen relevant war. 

Hangbereich aus dem eine 

Hangbewegung ihren Ausgang 

nimmt. 

Der Auslöser/Anlass für das 

Versagen eines Hanges liegt in 

externen Faktoren. Dieser löst 

eine quasi sofortige Reaktion 

aus, die ihrerseits wieder Auslöser 

für die nächste Reaktion 

sein kann (Kausalitätskette). 

Die Auslöser reduzieren zum 

Beispiel die Festigkeit der im 

Hang anstehenden Gesteine. 

Mögliche Auslöser können sein: 

Niederschläge, Schneeschmelze, 

Frost- Tauwechsel, Erdbeben, 

Menschlicher Eingriff. 

Öffnungen an der Erdoberfläche 

über die Oberflächenwasser in 

den Untergrund eindringt. 

Hangbewegung mit großem 

Volumen und hoher Dynamik, 

die oftmals dafür sorgt, dass 

die Massen am Gegenhang 

weit aufbranden. Volumen > 

1.000.000m³. 

LfU Bayern 

LfU Bayern 

LfU Bayern 

LfU Bayern 

LfU Bayern 

LfU Bayern 

Allgemeine 

Geomorphologie 

Maßnahmen 

Rutschungsdynamik 

Anbruchformen 

Allgemeines 

Subrosionsprozess/Allgemein 

LfU Bayern Sturzprozess - 

Bergsturz 

same_ 

rel 

similar_ 

rel


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Seite 79 

Excel table with a unique ID for each term. This 

ID is used to establish the relations between the 

different languages and also to integrate these in 

the relational database. Fig. 6 shows an extract 

of this Excel table with the basic terms from 

Germany. 

2.2 “Harmonisation” of terms and methods 

“…A glossary will facilitate transdisciplinary 

and translingual cooperation as well as support 

the harmonization of the various methods…” 

(www.adaptalp.org). 

Striving for “Harmonization” of regional 

terms and methods seems to be a guiding principle 

not only in WP 5 of the AdaptAlp project but in 

multiple European cooperation projects. 

In the literature, a lot of definitions are 

used for the term harmonization. According to 

the business dictionary, harmonization is an 

“adjustment of differences and inconsistencies 

among different measurements, methods, 

procedures, schedules, specifications, or systems 

to make them uniform or mutually compatible” 

(www.businessdictionary.com). 

This definition implies some important 

points which are mentioned as main goals in many 

projects supported by the EU. The adjustment of 

differences and the achievement of compatibility 

also play a major role in work package 5: 

“AdaptAlp will evaluate, harmonise and improve 

different methods of hazard zone planning 

applied in the Alpine area. The comparison of 

methods for mapping geological and water risks 

in the individual countries” (www.adaptalp.org) 

will be brought into focus. 

Concerning the development of the 

multilingual glossary for geological hazards, the 

“Harmonization” is implemented by the following 

approach. 

German 

English 

id term definition reference topic topic term definition 

2001 Stauchwulst 

2002 Murwall 

2003 

2004 

2005 

Blocklandschaft 

Murkegel, 

-fächer 

Schwemmkegel, 

-fächer 

2006 Schuttkegel 

2007 Buckelfläche 

2008 Sturzmasse 

2009 Rutschmasse 

2010 

Rutschscholle 

2011 Sturzblock 

Wulst aus Gesteinsmaterial. 

Sie tritt vor allem an der 

Stirn einer Rutsch- oder 

Kriechmasse auf 

Murablagerung am 

seitlichen Rand des 

Murkanales 

Gelände, in dem weiträumig 

Blöcke und Gesteinsschollen 

verteilt sind. 

Herkunft der Blöcke in der 

Regel von großen Fels- od. 

Bergstürzen, aber auch von 

Talzuschüben. 

Unter Murkegel sind kegelförmige 

Ablagerungen v.a. 

an Gerinnen zu verstehen, 

deren Böschungswinkel 

meist mehr als 8-10° beträgt 

Sie sind oft noch durch die 

typischen dammartigen 

Wülste entlang des Randes 

eines ehemaligen Murstromes 

gekennzeichnet. 

Schwemmkegel weisen im 

Gegensatz zu Murkegeln 

meist Böschungswinkel von 

weniger als 10° auf, größere 

Geschiebeblöcke fehlen. 

Schuttkegel entstehen 

v. a. durch Steinschlag. 

Sie lagern sich an 

Steilwände und dort 

bevorzugt im Bereich von 

Steinschlagrinnen an 

Gelände, das durch 

unruhige Morphologie 

(weiche Formen) 

gekennzeichnet ist. 

Ablagerung infolge eines 

Sturzprozesses. 

Ablagerung infolge eines 

Rutschprozesses 

Teilweise im 

Verband befindlicher 

Gesteinskomplex, der als 

ganze Scholle abrutscht. 

Einzelblock >1m³, infolge 

eines Sturzprozesses. 

Fig. 8: Extract of the “suggested-terms list” for England 

Abb. 8: Auszug aus der vorgeschlagenen Begriffsliste für England 

LfU Bayern Ablagerungen accumulation toe???? 

LfU Bayern Ablagerungen accumulation 









Bloc 

Landscape???? 

coned debris/ 

detritus???? 

undulating 

area???? 

sliding bloc/clod/ 

massif???? 

LfU Bayern Ablagerungen accumulation (fall) bloc???? 

accumulation at the toe/foot 

of the main body. 

accumulation at flank of the 

main body. 

Area in which blocs are 

shared spacious. Bloc are 

comming from rock collapses, 

block falls or sags. 

Coned accumulation espacially 

at channels with a 

naturel slope of 8-10°. 

Coned accumulation espacially 

at channels with a 

naturel slope less than 10° 

and with no big blocs. 

"coned debris/detritus" are 

caused by rock falls. They 

accumulate at the rock face. 

Area which is characterized 

by undulating morphologie. 

Accumulation caused by a 

fall process. 

Accumulation caused by a 

slide process. 

A coplex of rocks which is 

sliding as one bloc/clod/ 

massif. 

One bloc (


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Seite 81 

2.2.1 Basic rules 

In order to tackle the complexity and ambiguity, 

found not only in German-speaking geology, 

but generally throughout Europe, a multilingual 

glossary shall be created. This glossary aims at 

international harmonization by providing the 

user with a selection of official terms used by 

the geological agency in a specific country and 

by setting relations to similar terms employed in 

other countries. Unlike many other glossaries, 

which are more like dictionaries working with 

direct translations; this glossary consists of terms 

and definitions which are used by the official 

agencies from the involved countries. So the big 

difference from many other word lists is the way 

of getting the topics. 

2.2.2 Data acquisition 

Basically the data acquisition is made during 

short visits in the involved countries. Building 

on the German “basic list”, in these talks “term 

after term” is discussed with the respective person 

responsible. With regard to linguistic problems, 

each “Harmonization” is carried out with the 

help of native speakers who also be well versed in 

the thematic of geological hazards. The terms are 

related in the following three forms: 

• Same meaning (the term has the same 

meaning in both languages) 

• Similar meaning (the term has a similar 

meaning in both languages) 

• Not existing (no term with the same or 

similar meaning exists) 

To facilitate the harmonization process, in the 

run-up to the visits, several national literature 

lists with suggested terms are worked out with 

the native speakers. These lists also contain short 

descriptions of the desired expressions and they 

are sent to the responsible persons for orientation 

and preparation. Furthermore, Fig. 7 shows an 

extract of the “suggested terms list” for England. 

A picture paints a thousand words, therefore also 

pictures and illustrations are used within the talks. 

2.2.3 Data preparation and presentation 

Concerning the data preparation, the main issues 

are already described in the technical description 

above. The central point to fully exploit the 

possibilities of the database structure is the correct 

setting of the relations between the different terms 

(over the ID). 

Regarding to the data presentation, at 

this stage of the project no final results can be 

shown. As mentioned in the introduction of this 

article, the main output of the project will be an 

online glossary which is linked to the homepage 

of the Bavarian Environment Agnecy (LfU). The 

layout of this web page should be clear and 

simple for everyone to use. Therefore existing 

online glossaries are compared and “bestpractice” 

examples are pulled out as inspiration. 

Fig. 8 shows the “Inter Active Terminology for 

Europe” glossary from the European Union which 

approximately fulfils the desired criteria for the 

geological hazard glossary. 

technical meaning. Although the structure of the 

model may seem complex, the multiple functions 

offered by external tables and the stronger data 

integrity fully compensate for a higher level of 

complexity. To achieve this complexity, not only 

the structure of the relational database but also 

the contents should satisfy the guidelines. The 

term “Harmonisation” is playing a central role 

in the work for the glossary where the contents 

are concerned. Only terms, which are officially 

used by the regional responsible agencies, 

are registered in the glossary and the relations 

between the different expressions are also defined 

by several experts. The topics in this glossary 

are not defined by a translation agency, which 

undoubtedly would have the linguistic ability 

but not the specialist background. Due to this 

approach, every involved country or region gets 

the chance to determine the terms and definitions 

they use and that procedure improves the overall 

result. The connection to the LfU – Homepage 

ensures accessibility for all interested persons. 

This is an important contribution to one of the 

main goals of the whole project, namely the 

improvement of the cooperation by the European 

countries in dealing with geological hazards. 

3. Conclusion 


Fig. 9: Screenshot of the online “Inter Active Terminology for Europe” from the EU (Source: http://iate.europa.eu) 

Abb. 9: Screenshot de online „Inter Active Terminology for Europe” der EU (Quelle: http://iate.europa.eu) 

As mentioned in the introduction, this article 

presents no final results because the project runs 

until February 2011. Nevertheless, provisional 

results, theoretical and practical approaches 

could be shown. The database model presented 

in this article fulfils all requirements stated 

by a multilingual glossary focusing on mass 

movements and other geological hazards. The 

multilingual concept provides the user with a 

direct translation of a term in a foreign language 

and sets relations to other terms based on its 

Karl Mayer 

Bavarian Environment Agency (LfU) 

(Office Munich) 


80636 Munich – GERMANY 

Bernhard Lochner 

alpS – Centre for Natural Hazard 

and Risk Management 

Grabenweg 3 

6020 Innsbruck - AUSTRIA

Hazard assessment and mapping of mass-movements in the EU 

Seite 82 

Seite 83 

MICHAEL MÖLK, THOMAS SAUSGRUBER, RICHARD BÄK, ARBEN KOCIU 


for Rapid Mass Movements 

(Rock Fall and Landslide) in Austria 

Standards und Methoden der Gefährdungsanalyse 

für schnelle Massenbewegungen 

(Steinschläge und Rutschungen) in Österreich 

Summary: 

This presents the Austrian approach for the documentation and prediction of landslides and 

rock falls from various inventories (GEORIOS - Geological Survey, Torrent and Avalanche 

Control, inventories of the federal states) via the hazard zone planning leading to the 

development of process related susceptibility maps. The different legal obligations of the 

respective organizations leads to different results regarding the type, the extent and the quality 

of the expertise. 

Introduction 

In Austria there are several public organizations 

([12] HÜBL et al. 2009) involved in the assessment 

of rapid gravitational mass movements such 

as rock falls and landslides. Inventories of such 

events are maintained by the Austrian Torrent and 

Avalanche Control (WLV) and the Geological 

Survey of Austria (GBA) apart from independent 

assessments done by the national railway and 

road administrations. 

On the level of the federal administrations, 

different approaches to documenting and/or 

forecasting such mass movements are being followed. 

These organizations deal with those hazards using 

different approaches (method and target). 

As there are no legal instructions in Austria 

as to how to deal with the evaluation of mass 

movements, the federal states all follow a different 

course of action. Also, the status of available 

historical data is very different in the individual 

states. In some of the federal states, almost no data 

is available, others have collected a lot of data 

but it is not digitally available. And then there are 

states that can rely on a lot of digitally available 

data and are working on generating landslide 

susceptibility maps. The following provides a short 

summary about the efforts in the federal states. 

Mass-movement inventories in Austria 

Since 1978 the Geological Survey of Austria 

has been gathering and displaying information 

(e.g. documents, photos, inventory maps) 

about gravitational mass movements and other 

hazardous processes. Due to the increasing 

amount of data, the Department of Engineering 

Geology of the Geological Survey of Austria 

developed a complex data management system 

called GEORIOS. It consists of a Geographical 

Information System (GIS), which is the basis for 

the digital storage and display of data and overlay 

of different data types. Additionally the data 

management system consists of a relational data 

base, which manages additional thousands of 

meta-information (documents, photos etc.). 


Der „österreichische“ Weg zur Erfassung von historischen bzw. zur Vorhersage von zukünftigen 

Steinschlagprozessen und Rutschungen von den verschiedenen Ereigniskatastern (GEORIOS 

– Geologische Bundesanstalt, Wildbach- und Lawinenkataster, Ereigniskataster der Länder) 

über die Gefahrenzonenplanung bis zur Erstellung von Prozessdispositionskarten wird dargestellt. 

Dabei sind unterschiedliche gesetzliche Verpflichtungen und Zielsetzungen für die damit 

befassten Organisationen maßgeblich für die Art, den Umfang und die Qualität der erreichten 

Aussagen. 

Fig. 1: Inventory of mass movements in Austria (source Geol. B.-A.: www.geologie.ac.at) 

Abb. 1: Karte der Massenbewegungen in Österreich (Quelle: Geol. B.-A.: www.geologie.ac.at)


Seite 84 

Seite 85 

The database includes detailed 

information about the mass movements (geology, 

hydrology, geometric and geographical data, 

studies or tests carried out, mitigation measures) 

and the source of information (archives, etc.), and 

also information about who carried out the field 

work and added the data into the database. 

There are already 22,000 mass 

movements stored in the database. The 

compilation of a part of the mass movements 

in Austria is publicly accessible via the internet 

(www.geologie.ac.at) in German and English. 

However, the web application includes only 

events such as slides, rock falls, or more complex 

mass movements which have been published 

already in the media or the internet and are freely 

available for everyone ([16]KOCIU et al 2007). 

An engineering geological database, as 

well as a bibliographical database is also included 

in the GEORIOS system. 

In cooperation with the Geological 

Survey of Carinthia, the Geological Survey of 

Austria has created not just one “inventory map”, 

but a “level of information”, as is explained in the 

following ([17] KOCIU et al 2010): 

Level of information: 

• Process index map, map of phenomena 

(“Prozesshinweiskarte”, “Karte der 

Phänomene”): These kinds of maps can have 

different scales (1:50,000 and bigger) and 

can be of varying quality with information 

about process areas as phenomena of mass 

movements that have already happened. 

• The event inventory (“Ereigniskataster”) 

records only those processes for which an 

event date is known (5W–questions), it is 

independent of a scale and can contain 

processes without information on location. 

In Carinthia, a digital landslide inventory 

was created with historical events of the 

last 50 years ([1] BÄK et al 2005). 

Fig. 2: Event inventory of Carinthia with 5W-questions and 

quality remarks MAXO (M-sure; A-estimate; X-uncertain; 

O-unknown) 

Abb. 2: Ereignisdatenbank von Kärnten mit 5W-Fragen und 

Qualitätskriterien „MAXO“ 

• The inventory map/event map 

(“Ereigniskarte”) contains only information 

about processes for which an event date is 

known (5W–questions: What, When, Where, 

Who, Why). The symbols are correlated to 

process type and magnitude (triangle – small 

events, pentagon – great events). 

Fig. 3: Event map of Carinthia (brown – landslides; blue – earth 

flow; red – rock fall; green – earth fall) 

Abb. 3: Ereigniskarte von Kärnten 

• The thematic inventory map contains 

only information related to a type of 

process, categorized according to the 

quality of the data. 

Fig. 4: WLV-Inventory of mass movements in Austria (source: www.die-wildbach.at) 

Abb. 4: Ereignisdatenbank der WLV (Quelle: www.die-wildbach.at) 

The Austrian Torrent and Avalanche Control (WLV) 

also maintains an inventory covering torrential 

floods, avalanches, landslides and rock falls – the 

are chosen to develop susceptibility maps 

(different scales, processes) derived from existing 

data sets and maps ([30] POSCH-TRÖTZMÜLLER 

so called “Wildbach- und Lawinenkataster”. G., 2010): Main focus of Burgenland is 

concentrated on shallow landslides with an 

Standards of susceptibility/hazard 

assessment in Austria 

annual rate of movement of 1-2cm. For the 

prediction of landslide susceptibility based on 

morphological and geological factors, the method 

Because of the lack of a regulatory framework 

or technical standard concerning landslides and 

rock falls in Austria - only the course of actions 

concerning floods, avalanches and debris flows 

are regulated by law (ordinance of hazard zone 

mapping,[33] RUDOLF-MIKLAU F. & SCHMIDT 

F., 2004) - the federal states all follow a different 

course of action. 

For example, in Vorarlberg risk maps 

(susceptibility map, vulnerability map, risk map) 

were produced in the course of a university 

dissertation ([34] RUFF, 2005). For modelling, 

bivariate statistics (for landslides) and cost 

analysis (for rock fall) were used, working with a 

25x25m raster. The susceptibility, meaning spatial 

susceptibility, is presented in 5 classes (very low, 

low, medium, high, very high). The inventory map 

is included in the susceptibility map. On the other 

hand, the local department of the Austrian Service 

for Torrent and Avalanche Control (WLV) creates 

“hazard maps” within the “hazard zoning plan”. 

called “Weights of Evidence” was chosen ([15] 

KLINGSEISEN et al., 2006). Three (respectively 

4) hazard zones were classified ([“high Hazard”], 

“hazard”, “hazard cannot be excluded”, “no 

hazard”, [15] KLINGSEISEN et al., 2006). In 

Lower Austria up until now the susceptibility maps 

have been created using a heuristic approach 

based on geological expertise, historical data and 

interpretation of DEM and aerial photos. Three 

to ten classes of susceptibility are delineated at 

a scale ranging from 1:50,000 to 1:25,000 ([36] 

SCHWEIGL & HERVAS 2009). To offer assistance 

for the municipalities in land-use planning, 

landslide susceptibility maps were generated for 

the major settled areas in Upper Austria (OÖ). 

For each type of mass movement, the priority, 

which is a susceptibility class, was evaluated on 

the basis of the intensity and the probability of an 

event. The priority was classified in 3 stages (high 

– medium – low; [18] KOLMER, 2005). As these 

maps include the intensity and the frequency of 

In Upper Austria, Lower Austria, mass movements, they can be called “hazard 

Burgenland and Carinthia, different approaches maps” by definition. Nevertheless it has to be


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taken into account that the method of generating 

these maps included neither field work nor remote 

sensing techniques. The method of assessment is 

based solely on geological expertise. 

Using the digital geological map of 

Carinthia (1:50,000), the inventory map of mass 

movements (landslides and rock falls), DEM 

(10m x10m raster), land-use and lithologicalgeotechnical 

characteristics of bedrock and 

For a small study area in Styria, the Geological 

Survey of Austria generated a susceptibility map 

for spontaneous landslide (soil slips and earth 

flows) at a scale of 1:50,000 using neural network 

analysis ([35] SCHWARZ et al., 2009). Any 

susceptibility class is not a ranking of the degree 

of slope stability, but a description of the relative 

propensity/probability of a landslide of a given 

type and of a given source area to occur.). 

unconsolidated sediments, process-related 

At the Geological Survey of Austria 

susceptibility maps for Carinthia were generated in 

a collaboration of the Geological Survey of Austria 

(GBA) and the Geological Survey of Carinthia at 

a scale of 1:200,000 ([1] BÄK et al., 2005). Of 

course these maps still lack information about 

intensity and recurrence period or probability of 

occurrence. Due to the imprecision of input data 

used, the accuracy of predictions regarding the 

susceptibility for rapid mass-movements based on 

maps like the ones mentioned above is limited. 

(GBA), susceptibility maps in different scales and 

with different methods (heuristic approach, neural 

network analysis) have already been generated. ([17] 

KOCIU et al., 2010, [21] MELZNER et al., 2010, 

[38] TILCH et al., 2009, [39] TILCH et al., 2010, [40] 

TILCH et al., 2010, [41] TILCH et al 2009). 

Legal situation, requirements by the law, 

responsibility of different authorities 

The key feature for susceptibility/hazard 

mapping is a good documentation of historic 

Fig. 5: Susceptibility map for spontaneous shallow landslide at Gasen – Haslau ([35] Schwarz et al 2009). 

Abb. 5: Dispositionskarte für spontane, flachgründige Rutschungen im Bereich Gasen-Haslau ([35]Schwarz et al 2009). 

events, a thorough mapping of the phenomena 

involved and an accurate interpretation of the 

failure with the subsequent processes. 

The WLV is legally obliged to do an 

inventory of all events regarding natural hazards, 

such as torrential processes, avalanches, rock-falls 

and landslides in the so called “Wildbach- und 

Lawinenkataster – WLK” ([8] Forstgesetz 1975). 

The GBA defines its very own tasks, among others: 

“the assessment and evaluation of geogenically 

induced natural hazards". These inventories 

(WLV, GBA, geological surveys of provinces like 

Carinthia) are established to guarantee a complete 

documentation of processes and events that can 

eventually endanger infrastructure and/or people. 

The data collected in the inventories allow for 

better information and further evaluation of where, 

when, how often and with which intensities those 

events took place. These inventories can form 

an important basis for the elaboration of hazard 

maps and related hazard zones, which give the 

authorities good evidence to optimize land-use 

planning and avoid areas that tend to be exposed 

to natural hazards. For already developed areas, 

the assessment of the type of process, magnitude, 

run-out, location, frequency etc. allows for a better 

priority-rating and design of mitigation measures. 

The elaboration of hazard zone maps 

([8] Forstgesetz 1975 and [2] BGBl. 436/1976) 

for potentially endangered zones caused by 

natural hazards (except flooding by rivers and 

earthquakes, which are done by other authorities) 

for all communities is the task of the Austrian 

Torrent and Avalanche Control (WLV). 

The delineation of potential emmissionzones 

of rapid mass movements, such as rock falls 

and landslides, are not mandatory and therefore 

can be illustrated as “brown hazard indication 

areas” by the WLV. 

The legal implication of these indication 

areas lies in the obligation of the authorities 

issuing building permits to consult an expert to 

evaluate the hazard for the planned construction 

site explicitly, otherwise the community can be 

excluded from public funding for the financing of 

mitigation measures in the future. 

Standards, guidelines, official and legal documents 

Several standards issued by the IAEG (Internat. 

Association of Engineering Geology –UNESCO 

Working Party of World Landslide Inventory 

[42] to [47]) exist for the documentation and 

classification of landslides. Furthermore, for the 

documentation of landslide and rock fall events 

(avalanches and torrential processes are covered 

as well) there is a short course of the Universität 

für Bodenkultur Wien, Dpt. f. Bautechnik und 

Naturgefahren, Inst. f. Alpine Naturgefahren, 

which certifies documentalists for those processes. 

For the assessment and evaluation of rock 

fall processes and the design of protection 

measures an Austrian Standard is currently under 

development ([28] ONR 24810: Technischer 

Steinschlagschutz). 

State of the art in the practice 

The code of practice is to be brought up to the 

state of the art due to the absence of binding 

standards. The state of the art according to the 

“Wasserrechtsgesetz WRG 1959 §12a(1)” is 

defined in Austria as the following: The use of 

modern technological methods, equipment and 

modes of operation with proven functionality 

which represent the status of progress based on 

relevant scientific expertise. 

Rock fall hazard assessment 

The state of the art regarding the assessment and 

evaluation of hazard for rock fall processes can


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Seite 89 

be described by the following workflow. The 

methods to be applied are just roughly described, 

for a detailed description see the cited literature. 

Depending on the objective of the assessment, the 

tools to be applied may vary in respect to the scale 

of the result, being more coarse at regional scale 

and detailed at slope-scale. 

Standard procedure for the assessment of rock fall 

hazards (best practice): 

Preparation 

• Definition of the boundaries of the project 

area in compliance with the stakeholder 

• Acquisition of basic data (topografic maps, 

geology, land use, literature, studies etc.) 

• Collection of historic event information 

(written and oral) 

Field work: 

• Collection of properties of the forest (if 

relevant), identification (by field work and/ 

or according to e. g. [12] JABOYEDOFF 

1999) and 

• Evaluation of detachment areas 

description of discontinuities 

(type, dip/direction, opening, filling …), 

properties of rock mass, 

relevant failure mechanisms, 

probabilistic distribution of 

joint-bordered rock bodies 

• Scree slopes: block-size distribution 

(statistics) 

• Analysis of rock fall processes ([22] 

MELZNER et al 2010, [23] MELZNER et al 

2010, [24] MÖLK 2008): 

Rough estimation of run out e. g. by 

shadow angle (regional scale) 

2D or 3D modelling (probabilistic): 

provides run out length, energy and 

bouncing-height distributions for slopescale 

problems 

Fig. 6: Delineation of potential conflict areas at regional extent 

using an empirical model ([21] Melzner et al 2010). 

Abb. 6: Abgrenzung potenzieller Wirkungsbereiche mittel einfachen 

empirischen Modellansätzen ([21] Melzner et al 2010). 

For the design of mitigation measures, a 

probabilistic approach is going to be defined 

as a standard procedure in Austria ([28] ONR 

24810) following the concept of partial factors of 

safety ([26] EUROCODES) for actions/resistances 

and varying accepted probabilities of failure 

depending on the casualty and reliability-classes 

of [27] Eurocode 0. 

Landslide hazard assessment 

General 

The combination of a rotational and a translational 

sliding mechanism is called a compound slide. 

These may develop in horizontally stratified soils 

and rocks, where the upper part of the slope shows 

Landslides present complex natural phenomena 

for both the variability of processes and the 

dimensions. A landslide may exhibit a translational 

sheet slide of some square meters involving the 

ground surface or a deep seated mass movement 

of several cubic kilometres. 

Rapid landslides with reference to [6] 

CRUDEN & VARNES (1996) feature velocities 

of some metres per minute to several meters per 

second. In Austria, the main processes exhibit 

different slides and debris slides. Very rapid to 

rapid flow slides, which one can find for example 

in Scandinavia or in Canada, have no relevance 

in Austria. 

Slides include rotational, translational 

and compound slides. Rotational slides own a 

circular sliding surface, which results from shear 

failure in relatively homogenous rock or soil of low 

a rotational failure which is constrained by a plane 

of weakness at the base (e. g. a claystone layer). 

A process that frequently can be observed 

in Austria are debris slides (e. g. Gasen and Haslau 

2005, Vorarlberg). These failures occur in porous 

soils, especially after extraordinary water input 

resulting from precipitation and/or snow melt 

leading to an excess of pore water pressure. The 

mass movement often starts as a rotational slide, 

which turns into a debris flow down slope. 

When assessing landslide hazards, it 

is important to distinguish between preparatory 

factors and the triggers ([46] WL/WPLI 1994). The 

triggering of the occurrence of a mass movement is 

the last step of destabilization over a longer period 

of time. Concerning [37] THERZAGHI (1950) the 

stability of slopes is stated by the factor of safety, 

which is expressed by the ratio between driving 

strength. Translational 

slides take place in 

rock on forgiven more 

or less planar features 

like bedding planes, 

joints etc. The failure 

results when the shear 

resistance on the plane 

is exceeded. Relatively 

often one can find 

these slides in the soil 

cover of the ground, 

called sheet slides, 

where the sliding 

surface is formed by a 

weak clay layer, such 

as a gley horizon in the 

range of groundwater 

fluctuations. 

Fig. 7: An Example of changes of the factor of safety with time after [46] WL/WPLI (1994) 

Abb. 7: Beispiel für die Veränderung der Sicherheit eines Einhanges über die Zeit, 

nach [46] WL/WPLI (1994)


Seite 90 

Seite 91 

forces and resisting forces. Stable slopes feature a 

factor of safety over one, meaning that the resisting 

forces exceed the driving forces. If the driving 

forces are greater than the resisting forces the slope 

fails, i.e. the factor of safety drops under one. 

Fig. 5 ([46] WL/WPLI 1994) shows the 

development of a stable slope to one that fails. 

Since the slope is exposed to weathering, erosion 

processes etc. the factor of safety of the slope 

decreases to the point where it is close to failure 

(marginally stable). At this point the slope is 

susceptible to many triggers. 

When assessing landslide hazard the 

following information is needed regarding the 

ground conditions: 

• geology and structures 

• hydrogeology, 

• type of process 

• velocity of the process 

• geotechnical properties of materials 

involved 

• potential role of human activities (triggers?). 

State of the practice in landslide assessment 

Conventional methods are based on observations 

of potentially unstable slopes. Aerial photos, 

both stereographic and orthophotos, have been 

used since decades to detect these slopes by 

characteristic geomorphological phenomena in 

combination with available geological maps ([4] 

BUNZA 1996, [14] KIENHOLZ 1995). This first 

analysis is completed by mapping in the field. The 

data are commonly presented in landslide hazard 

maps, which show the spatial distribution of 

different hazard classes. Additionally chronicles, 

which occasionally exist at the town halls, turned 

out to be very useful. 

State of the art in landslide assessment 

For several years, high resolution Lidar data 

have been available for most regions in Austria 

bearing landslide activity. They are a powerful 

tool to recognize geomorphological structures 

of landslides ([49] ZANGERL et al., 2008). A 

main advantage of Lidar data in comparison 

to conventional photos is the information on 

shaded areas and of areas covered with wood. 

Additionally, remote sensing systems (e.g. 

airborne and satellite-based multispectral and 

radar images) provide information on unstable, 

slowly creeping slopes, which may fail and 

transfer into a rapid moving masses ([31] PRAGER 

et al., 2009). 

Until recently, susceptibility/hazard 

maps in Austria were often made on demand. 

For some years authorities (LReg Kärnten, WLV 

Oberösterreich und Vorarlberg) are going to make 

comprehensive hazard maps giving a basis on 

decision-making for land use and development. 

Landslide inventories (databases of WLV, GBA, 

several federal states) in combination with GIS 

applications are used to get rapid information to 

areas prone to landslides. 

Collected surface data in combination 

with subsurface data gained from trenches 

and boreholes or seismic refraction, groundpenetrating 

radar and electrical resistivity profiles 

allow for the drawing of an underground-model 

and deduce the type of failure mechanism which 

is most likely to occur. 

Geotechnical data are also required 

to assess the factor of safety and the probability 

of failure by means of analytical calculations 

or numerical modelling (e.g. [29] Poisel et al. 

2006). Additional information on the process 

can be provided by a monitoring system. This 

serves as a check for the taken assumptions 

and an evaluation of the mechanical model. 

Furthermore, a monitoring allows the prediction 

of failure time under certain circumstances (e.g. 

[9] FUKUZONO 1985, [19] KRÄHENBÜHL 

2006, [32] ROSE & HUNGR 2007) 

Future development 

The development of forecast-models for the 

prognosis of the location and/or time of rapid 

gravitational mass movements to take place 

or even the meteorological settings which will 

trigger such events is at an early stage. Due to 

the fact that the authorities are strongly asking for 

such tools, many practitioners and scientists are 

focusing on that topic. 

The multitude of parameters influencing 

the development of the erosion processes in 

question will keep the stakes high and will not 

allow for providing the authorities with the accurate 

models they ask for within a considerable time. 

Given the necessary detailed parameters, such as 

geology, hydrogeology, geotechnical parameters 

etc., triggering, influencing or allowing for the 

processes in question are at hand, and all the 

necessary models are developed, it is highly likely 

that they will work in certain regions with similar 

or corresponding geological, morphological and 

meteorological conditions only. 

The accuracy of these models will 

necessarily depend highly on a thorough 

calibration with well-documented events. 

This emphasizes the necessity of a consistent 

documentation of events, to provide the modeldevelopers 

with calibration data. 

This means that the expertise of experts 

applied at defined locations with all the necessary 

field work and assessment of natural parameters, 

fed in apt models will not become obsolete in 

the near and very probably not even in the far 

future. Models showing the disposition of a given 

environment to tend to mass-movements and 

also forecasting the location, time and run-out 

of such processes will be a precious tool for the 

experts although a replacement of a thorough 

evaluation of the conditions on site is not to be 

expected anytime. 


Michael Mölk 

Forsttechnischer Dienst für 

Wildbach und Lawinenverbauung, 

Geologische Stelle 

Liebeneggstr. 11 

6020 Innsbruck 

michael.moelk@die-wildbach.at 

Thomas Sausgruber 

Forsttechnischer Dienst für 

Wildbach und Lawinenverbauung 

Geologische Stelle 

Liebeneggstr. 11 

6020 Innsbruck 

thomas.sausgruber@die-wildbach.at 

Richard Bäk 

Abt. 15 Umwelt 

Geologie+Bodenschutz 

Flatschacher Straße 70 

9020 Klagenfurt 

richard.baek@ktn.gv.at 

Arben Kociu 

Geologische Bundesanstalt 

Fachabteilung Ingenieurgeologie 

Neulinggasse 38 

1030 Wien 

arben.kociu@geologie.ac.at


Seite 92 

Seite 93 


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I., SKOLAUT, Ch., TILCH, N. & TOTSCHNIK, R. (2009): Alpine 

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[35] SCHWARZ, L., TILCH, N. & KOCIU. A. (2009): 

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HUGO RAETZO, BERNARD LOUP 

Geological Hazard Assessment in Switzerland 

Geologische Gefahrenbeurteilung in der Schweiz 

Summary: 

Geological hazard assessments are based on Swiss laws dealing with natural hazards. 

Guidelines are published by the Federal Office for the Environment (FOEN/BAFU). According 

to the integrated risk management, the methods are applied for all natural hazards (landslides, 

floods, snow avalanches). The hazard maps are dealing with five degrees: high (red), medium 

(blue), low (yellow), residual (yellow-white), no hazard (white). 


Geologische Gefahren werden in der Schweiz gemäß den eidgenössischen Gesetzen über den 

Wald und den Wasserbau erhoben und beurteilt. Dazu hat das zuständige Bundesamt (heute 

das Bundesamt für Umwelt BAFU) entsprechende Empfehlungen und Richtlinien veröffentlicht. 

Im Sinne des integralen Risikomanagements werden für alle Gefahrenprozesse vergleichbare 

Methoden angewendet und anschließend in der Planung umgesetzt. Das gilt für geologische 

Massenbewegungen, Hochwasser und Lawinen. Für diese Prozesse werden Gefahrenkarten 

erstellt, die immer fünf Gefahrenstufen ausscheiden: Hohe, mittlere und geringe Gefahr sowie 

Restgefährdung und keine Gefährdung. Daraus entstehen die roten, blauen, gelben, gelb-weiß 

gestreiften und weißen Zonen auf den Gefahrenkarten. 

Introduction 

Switzerland is a country exposed to many natural 

hazards. These hazards include earthquakes, floods, 

forest fires, snow avalanches, rock falls and debris 

flows. More than 6% of Switzerland is affected by 

hazards due to slope instability. These areas occur 

mainly in the Prealps and in the Alps. The Randa 

rock avalanches of 1991 are a good example of the 

potential of such hazards. Thirty million m 3 of fallen 

debris cut off the valley for two weeks. In another 

case, a landslide was reactivated with historically 

unprecedented rates of displacement up to 6 m/ 

day, causing the destruction of the village of Falli- 

Hölli in the year 1994. 

The legal and technical background 

conditions for the protection against landslides 

have undergone considerable changes since the 

80’s. The flooding of 1987 promoted the federal 

authorities to review criteria governing natural 

hazard protection. The Federal Flood Protection 

Law and the Federal Forest Law came into force in 

1991. Their purpose is to protect the environment, 

human lives and property from the damage caused 

by water, mass movements, snow avalanches and 

forest fires. Following the promulgation of these 

new regulations, greater emphasis has been 

placed on preventive measures. Consequently, 

hazard assessment, the identification of protection 

objectives, purposeful planning of preventive 

measures and the limitation of the residual 

risk are of central importance. The cantons are 

now required to establish inventories and maps 

denoting areas of hazards, and to take them 

into account in the land use planning. For the 

improvement of the inventories and the hazard 

maps, the federal government provides subsides 

to the cantonal authorities (50%). 

In a first step the landslides are identified 

and classified. During this phase inventories and 

maps of phenomena are established. In a second 

step the hazard of landslides is assessed according 

to the methods used in the Swiss strategy against 

all natural hazards (e.g. floods, avalanches). The 

hazard assessment is then integrated into land use 

planning and in the risk management (3. step). 

First step: Hazard identification 

Landslides can be classified according to the 

estimated depth of the sliding plane (< 2m: shallow; 

2-10 m: intermediate; >10 m: deep) and the long 

term mean velocity of the movements (< 2 cm/year: 

substabilised; 2-10 cm/year: slow; > 10 cm/year: 

active). These depth and velocity parameters are 

not always sufficient to estimate the potential 

danger of a landslide. Differential movements must 

also be taken into account since they can generate 

buildings to topple or cracks to open. 

Rock falls are characterized by their speed 

(< 40 m/s), the size of their elements (Østone < 0.5 m, 

Øblock > 0.5 m) and the volumes involved. Rock 

avalanches with huge volumes (v > 1million m 3 ) 

and high speed (> 40 m/s) can also happen 

although these are rare. 

Due to heavy rainfall, debris flows and 

very shallow landslides are frequent in Switzerland. 

These are moderate volume (< 20,000 m 3 ) and 

high speed features (1-10 m/s). These phenomena 

are very dangerous and annually cause important 

traffic disruptions and fatalities. 

A map of landslide phenomena and 

an associated technical report provide signs 

and indications of slope instability as observed 

in the field. The map represents phenomena 

related to dangerous processes and delineates the 

vulnerable areas. 

Field interpretation of these phenomena 

allows areas vulnerable to landslides to be 

mapped. This is based on the observation and 

interpretation of landforms, on structural and 

geomechanical properties of slope instabilities,


Seite 96 

Seite 97 

and on historical traces. Extensive knowledge of 

past and current events in a catchment area is 

essential if zones of future instability are to be 

identified. 

Some recommendations for the uniform 

classification, representation and documentation 

of natural processes have been established by the 

Swiss federal administration. Consequently, the 

definition of features on a natural hazard map is 

based on a uniform legend for landslides, floods 

and snow avalanches. The different phenomena 

are represented by different colours and symbols. 

RED: high hazard 

• People are at risk of injury both inside and outside buildings. 

• A rapid destruction of buildings is possible. 

or: 

An additional distinction is made between 

potential, inferred or proved events. According to 

the scale of mapping (e.g. 1:50,000 for the Master 

Plan, 1:5,000 for the Local Plan), this legend may 

contain a large number of symbols. 

Inventories: Recommendations for 

the definition of a uniform Register for slope 

instability events has been developed, including 

special sheets for each phenomenon (landslides, 

floods, snow avalanches). Each canton is currently 

compiling the data for its own register. These 

databases (StorMe) are transferred to the FOEN to 

• Events occurring with a lower intensity, but with a higher probability of occurrence. In this 

case, people are mainly at risk outside buildings, or buildings can no longer house people. 

The red zone mainly designates a prohibition domain (area where development is prohibited). 

BLUE: moderate hazard 

• People are at risk of injury outside buildings. Risk is considerably lower inside buildings. 

• Damage to buildings should be expected, but not a rapid destruction, as long as the 

construction type has been adapted to the present conditions. 

The blue zone is mainly a regulation domain, in which severe damage can be reduced by 

means of appropriate protective measures (area with restrictive regulations). 

YELLOW: low hazard 

• People are at slow risk of injury. 

• Slight damage to buildings is possible. 

The yellow zone is mainly an alerting domain (area where people are notified at possible 

hazard). 

YELLOW-WHITE HATCHING: residual danger 

Low probability of high intensity event occurrence can be designated by yellow-white hatching. 

The yellow-white hatched zone is mainly an alerting domain, highlighting a residual danger. 

WHITE: no danger or negligible danger, according to currently available information. 

allow an overview of the different natural disasters 

and potential associated damage in Switzerland. 

Second step: Hazard assessment of landslides 

Hazard is defined as the occurrence of a potentially 

damaging natural phenomena within a specific 

period of time in a given area. Hazard assessment 

implies the determination of the magnitude or 

intensity of an event over time. Mass movements 

often correspond to gradual (landslides) or unique 

(falls, debris flows) events. It is sometimes difficult 

to make an assessment of the return period of 

a massive rock avalanche, or to predict when a 

dormant landslide may reactivate. 

Some federal recommendations have 

been proposed in the 90’s for the management 

of landslides and floods. Since 1984 similar 

recommendations have already existed for snow 

avalanches. Hazard maps, according to the federal 

“recommendations“ (guidelines), express three 

degrees of danger, represented by corresponding 

colours: red, blue and yellow (Fig. 1). The various 

hazard zones are delineated according to the 

landslide phenomena maps, the register of slope 

instability events and additional documents. 

Numerical models (analysis of block trajectories, 

calculations of factors of safety) may be used to 

determine the extent of areas endangered by rock 

falls, or to present quantitative data on the stability 

of a potentially unstable area. 

A chart of the degrees of danger has been 

developed in order to guarantee a homogeneous 

and uniform means of assessment of the different 

kinds of natural hazards across Switzerland 

(floods, snow avalanches, landslides…) – for 

example, Fig.1 for fall processes. Two major 

parameters are used to classify the danger: the 

intensity, and the probability (frequency or return 

period). Three degrees of danger have been 

defined. These are represented by the colours red, 

blue and yellow. The estimated degrees of danger 

have implications for land use. They indicate the 

level of danger to people and to animals, as well 

as to property. In the case of mass movement, 

people are considered safer inside the buildings 

than outside. 

A description of the magnitude of 

potential damage caused by an event is based on 

the identification of threshold values for degrees 

of danger, according to possible damage to 

property. The intensity parameter is divided into 

three degrees: 

High intensity: People and animals are at risk 

of injury inside buildings; heavy damage to 

buildings or even destruction of buildings is 

possible. 

Medium intensity: People and animals are 

at risk of injury outside buildings, but are at 

low risk inside buildings; lighter damage to 

buildings should be expected. 

Low intensity: People and animals are slightly 

threatened, even outside buildings (except 

in the case of stone and block avalanches, 

which can harm or kill people and animals); 

superficial damage to buildings should be 

expected. 

Criteria for the intensity assessment: 

There is generally no applicable measure to define 

the intensity of slope movements. However, 

indicative values can be used to define classes 

of high, mean and low intensity. Applied criteria 

usually refer to the zone affected by the process, 

or to the threatened zone. 

For rock falls, the significant criterion is the 

impact energy in the exposed zone (translation 

and rotation energy). The 300 kJ limit corresponds 

to the impact energy to which can be resisted 

by a reinforced concrete wall, as long as the 

structure is properly constructed. The 30 kJ limit


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Seite 99 

Phenomena Low intensity Medium intensity High intensity 

Rock fall E < 30 kJ 30 < E < 300 kJ E > 300 kJ 

Rock avalanche - - E > 300 kJ 

Landslide v ≤ 2 cm/y v : 2-10 cm/y v>10 cm/year 

Earth flows and 

debris flows 

dv, D, T dv, D, T dv, D, T 

potential e < 0.5 m 0.5 m < e < 2 m e > 2 m 

real - h < 1 m h > 1 m 

v > 0.1 m/day for 

shallow landslides; 

displacement > 1 m 

per event 

E: kinetic energy; e: thickness of the unstable layer; h: height of the earthflow deposit; v: long term mean 

velocity, dv: variation of velocity (accelerations), D: differential movements, T: thickness of the landslide. 

correlated with recurrent meteorological conditions. 

The probability of mass movement occurrence 

should mainly be established for a given duration of 

land use. Thus, the probability of potential damage 

during a certain period of time, or the degree 

of safety of a specific area should be taken into 

account, rather than the frequency of dangers. 

The probability of occurrence and the 

return period can be mathematically linked, if 

attributed to the same reference period: 

p = 1 – (1 – 1/ T) n 

Whereby p is the probability of occurrence, n 

represents the given time period (for example 30 

or 50 years), and T is the return period. 

For example, considering a time period of 30 

years, an event with a 30-year return period has 

a 64% probability of occurrence (or about 2 in 

3), of 26% (or about 1 in 4) for a 100-year return 

period, and of 10% (or about 1 in 10) for a 300- 

year return period. 

The calculation of the probability of 

occurrence clearly shows that even for a rather 

high return period (300 years), the residual danger 

remains not significant. 

In principle, the probability scale does 

not exclude very rare events, neither does it 

exclude the intensity scale for high magnitude 

events. Hazards with a very low probability of 

occurrence are usually classified as residual 

dangers under the standard classification. In the 

corresponds to the maximum energy that oak- 

converted to danger classes. Other criteria as 

wood stiff barriers can resist (e.g. rail sleeper). 

For rock avalanches, the high intensity class 

(E > 300 kJ) is always reached in the impact zone. 

The target zones affected by block avalanches 

of low to medium intensity can only be roughly 

delineated. Therefore, it is recommended not to 

artificially delineate zones affected by low to 

medium intensities. 

Most landslides: A low intensity movement has an 

annual mean speed of lower than 2 cm per year. 

A medium intensity has a speed ranging from 

one to 10 cm per year. The high intensity class 

is assigned to velocities higher than 10 cm per 

velocity changes or accelerations (dv), differential 

movements (D) and thickness of the landslide (T) 

can lead to increase resp. to reduce the intensity 

class as derived from the long term velocity. 

For earth flows and debris flows, 

the intensity depends on the thickness of the 

potentially unstable layer. The boundaries defining 

the three intensity classes are set at 0.5 m and 2 m. 

Probability: Probability of landslides is defined 

according to three classes. The class limits are set 

at 30 and 300 years and are equivalent to those 

established for snow avalanches and floods. The 

100-year limit corresponds to a value applied in 

INTENSITY 

low medium high 

RED 

BLUE 

YELLOW 

YELLOW / WHITE 

year and to shear zones or zones with clear 

the design of flood protection structures. 

differential movements (D). It may also be assigned 

The results of probability calculations to 

if reactivated phenomena have been observed or, 

if horizontal displacements greater than one meter 

per event may occur. Finally, the high intensity 

determine if mass movements occur remain very 

uncertain. Unlike floods and snow avalanches, mass 

movements are usually non-recurrent processes. 

high 

medium 

PROBABILITY 

low 

very low 

class can also be assigned to very rapid shallow 

landslides (speed > 0.1 m/day). In the area affected 

by landsliding field, intensity criteria can be directly 

The return period, therefore, only has a relative 

meaning, except for events involving stone and 

block avalanches and earth flows, which can be 

Fig. 1: Matrix for the assessment of hazards 

Abb. 1: Matrix für die Gefahrenbeurteilung


Seite 100 

Seite 101 

domain of dangers related to mass movements, 

the limit for a residual danger has been set for an 

event with a 300-year return period. 

The degree of hazard is defined in a 

hazard matrix based on intensity and probability 

criteria (Raetzo & Loup 2009). The resulting 

hazard map is mainly used for planning (land 

use), while the design of protection measures 

needs more detailed investigations. In general 

the methods used are related to the product, 

scales and the risk in order to respect economic 

criteria: low efforts are done for the Swiss 

indicative map (level 1), important efforts 

are done when a hazard map is established 

or reviewed (level 2). Detailed analyses and 

engineering calculations are foreseen for the 

planning of countermeasures (level 3). Applying 

this concept rising efforts for geological 

investigations are planned when the assessment 

on the second or third level takes place. 

Third step: Land use planning and risk management 

The hazard map is a basic document used in 

land use planning. Natural hazards should be 

taken into account particularly in the following 

situations: 

• Elaboration and improvement of cantonal 

Master Plan and Communal Local Plans for 

land use. 

• Planning, construction, transformation of 

buildings and infrastructures. 

• Granting of concessions and planning 

for construction and infrastructural 

installations. 

• Granting of subsidies for building and 

development (road and rail networks, 

residences), as well as for slope stabilisation 

and protection measures. 

According to Art. 6 of the Federal Law for Land 

use Planning, the cantons must identify all areas 

that are threatened by natural hazards. 

The cantonal Master Plan is a basic 

document for land use planning, infrastructural 

coordination and accident prevention. It consists 

of a map and a technical report, and is based on 

studies. The Master Plan allows for deciding the 

following: 

• It shows how to coordinate activities 

associated with different land uses. 

• It identifies the goals of planning and 

specifies the necessary stages. 

• It provides legal constraints to the 

authorities in charge of land use planning. 

The objectives of the Master Plan with respect to 

natural hazards are: 

• To early detect conflicts between land use, 

development and natural hazards. 

• To refine the survey of basic documents 

concerning natural hazards. 

• To formulate principles that can be applied 

by the cantons to the issue of protection 

against natural hazard. 

• To define necessary requirements and 

mandates to be used in subsequent 

planning stages. 

The constraints on Local Planning already allow 

and ensure appropriate management of natural 

hazards with respect to land use. The objective 

of these constraints is to delineate danger zones 

by highlighting restrictions, or to establish legal 

frameworks leading to the same ends. 

At the same time danger zones can be 

delineated on the local plan with areas suitable 

for construction as well as additional protection 

zones. 

The degrees of danger are initially assigned 

according to their consequences for construction 

activity. They must minimise risks to the safety 

of people and animals, as well as minimising 

as possible damage to property. In agricultural 

zones, buildings affected by different degrees of 

danger are constrained by the same conditions as 

those in built-up areas. 

Conclusions 

In Switzerland legal and technical references are 

published to clarify which responsibilities the 

authorities have and how the assessment has to 

be done in order to apply the concept of integral 

risk management. The hazard map indicates 

which areas are unsuitable for use, according 

to existing natural hazard. The integration of 

hazard maps into land use planning (including 

construction conditions, building licences) 

and the development of protective measures to 

minimise damage to property are main objectives. 

When the hazard map is compared with 

existing land use conflicts may occur. Since it is 

difficult or impossible to change land use, specific 

construction codes are required to reach the 

desired protection level. Hazard maps are also 

considered in planning protective measures as 

well as the installation of warning systems and 

emergency plans. The federal recommendations 

are on attempt to mitigate natural disasters by 

restricting development on unstable areas. 


Hugo Raetzo 



3003 Bern 

Schweiz 

Bernard Loup 



3003 Bern 

Schweiz 


BUNDESAMT FÜR RAUMPLANUNG, BUNDESAMT FÜR 

WASSERWIRTSCHAFT & BUNDESAMT FÜR UMWELT, WALD UND 

LANDSCHAFT, (1997). 

Empfehlungen, Berücksichtigung der Massenbewegungsgefahren bei 

raumwirksamen Tätigkeiten, EDMZ, 3000 Bern. 

CRUDEN D.M. UND VARNES D.J.: 

Landslide types and processes. In: A. Keith Turner & Robert L. Schuster 

(eds): Landslide investigation and mitigation: 36-75. Transportation 

Research Board, special report 247. Washington: National Academy Press, 

1996. 

KIENHOLZ, H., KRUMMENACHER, B. et al.: 

Empfehlungen Symbolbaukasten zur Kartierung der Phänomene Ausgabe 

1995, Mitteilungen BUWAL Nr. 6, 41 S., Reihe Vollzug Umwelt VU- 

7502-D, Bern 1995. 

RAETZO et al.: 

Hazard assessment of mass movements – codes of practice in Switzerland, 

International Association of Engineering Geology IAEG Bulletin, 2002. 

RAETZO, H. & LOUP, B.; BAFU: 

Schutz vor Massenbewegungen. Technische Richtlinie als Vollzugshilfe. 

Entwurf 9. Sept. 2009. 

VARNES, D.J. and IAEG Commission on Landslides and other Mass- 

Movements: 

Landslide hazard zonation: a review of principles and practice. The 

UNESCO Press, Paris, 1984.


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STEFANO CAMPUS 

Landslide Mapping in Piemonte (Italy): 

Danger, Hazard & Risk 

Kartierung von Rutschungen im Piemont (Italien): 

Gefahren & Risiken 

Summary: 

This paper briefly describes the legal framework of landslide danger, hazard and risk mapping 

in Italy and Piemonte. Laws or rules that indicate how a landslide analysis (danger, hazard, risk) 

has to be done, do not exist. As a general remark, it has to be observed that public legislation 

defines general principles and lines of conduct, functions, activities and authorities involved, 

while the regional administrations apply restrictions on land use through different regional laws. 

Keywords: Landslide, danger, hazard, risk, Piemonte, Italy 


Diese Abhandlung beschreibt kurz den gesetzlichen Rahmen der Kartografie von Rutschungsgefahren 

und -risiken in Italien und im Piemont. Es gibt keine Gesetze oder Verordnungen darüber, 

wie eine Rutschungsanalyse (Gefahren und Risiken) auszuführen ist. Als eine allgemeine 

Bemerkung ist festzustellen, dass die öffentliche Gesetzgebung allgemeine Prinzipien und 

Richtlinien, Funktionen, Aktivitäten und betreffende Befugnisse festlegt, die Regionalverwaltungen 

hingegen erlegen auf der unterschiedlichen landesgesetzlichen Basis Einschränkungen 

hinsichtlich der Bodennutzung auf. 

Schlüsselwörter: Rutschung, Gefahr, Gefährdung, Risiko, Piemont, Italien 

Introduction 

When facing a natural hazard, risk management 

can be divided in several stages: 

a) danger characterization, hazard assessment 

and vulnerability analysis; 

b) risk evaluation and assessment; 

c) risk prevention (protective works, land use 

regulation, monitoring, etc.); 

d) crisis and post-crisis management; 

e) feedback from experience. 

It is essential to properly distinguish the three 

aspects of landslides studies: 

• DANGER. Threat characterization (typology, 

morphology even quantitative, inventory…); 

• HAZARD. Spatial and temporal probability, 

intensity and forecasting of evolution 

(scenarios) are needed; 

• RISK. Interaction between a threat having 

particular hazard and human activities. We 

need vulnerability and damage analysis. 

These differences are theoretically well known by 

all technicians but often there are some problems 

when they have to be applied in a legal framework. 

So, it is not so unusual to find inventory maps used 

as hazard maps or damage maps called risk maps. 

Therefore, we have to distinguish two situations: 

1) Landslides studies that have no influence from 

legal point of view. Typical cases are the studies 

carried out by universities about relevant 

landslides. The aim is, for example, to understand 

the mechanical features of instability or to study 

different ways of evolution of the phenomenon 

(scenarios) in order to assess residual risk. Any 

method to assess landslide hazard and risk can 

be used. They include statistical, deterministic, 

numerical, etc. methods for hazard and 

qualitative or matrix calculus for risk. Landslide 

inventory can be made by means of historical, 

morphological, etc. approach. 

2) Landslide studies that have direct consequences 

to land planning laws, at local scale or higher. 

GIS methods allow for performing analyses 

over wide areas that are useful to be included 

in basin plans or master plans. National or local 

laws can require standard ways to present the 

results (common graphical signs on the maps, 

for example). 

Legal framework in Italy and Piemonte 

High Level Legislation (national level) 

The national Law n. 445/1908 (Transfer and 

consolidation of unstable towns) and Royal 

Decree R.D. n. 3267/1923 (Establishment of areas 

subject to hydro-geological constrains) were the 

first public regulations on land use planning. At 

the beginning of ‘70s, land use management was 

transferred to the regions. 

The national Law n. 183/1989 

introduced land use planning at a basin scale: the 

government sets the standards and general aims 

without fixing a methodology to analyze and 

evaluate the dangers, hazards, and risks related 

to natural phenomena. The same law designated 

the Autorità di Bacino (Basin Authorities) whose 

main goal is to draw up the Basin Plan, a tool for 

planning actions and rules for conservation and 

protection of the territory. 

About Po basin, the last plan adopted 

in 2001 is called PAI (Piano per l’Assetto 

Idrogeologico or Hydrogeological System Plan 

of River Po Basin). It tries to verify the geological 

instability of the whole territory as regards the 

land use planning through a process of upgrading 

and feedback with the local urban management 

plans. Moreover, all the municipalities are 

classified according different risk levels, mainly 

from a qualitative point of view. For landslides it 

has two atlases (1:25,000 scale):


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1) Atlas of Hydro-geological Risks (landslides, 

floods, alluvial fans, avalanches) at the 

municipal level. Every municipality is valued 

on the basis of the hazard, vulnerability 

and expected damage. Landslide hazard is 

function of ratio between area of landslides 

within municipal boundaries and whole area 

of municipality. 

It has 4 qualitative classes: 

• R1-moderate risk. Social damages and few 

economic losses are possible. 

• R2-medium risk. Few damages to buildings 

and infrastructures without loss of 

functionality. 

• R3-high risk. Problems to human safety. 

Many damages and economic losses. 

• R4-very high risk. Deaths and severe 

injuries are possible. 

2) Atlas of Landslides. It is an inventory, in 

which polygons and points are divided in 3 

classes (fig. 1): 

• Fa-Area with Active Landslides (“very 

high hazard”). No new buildings or 

infrastructures are allowed. Only measures 

of protection and reduction of vulnerability; 

• Fq-Area with Quiescent Landslides (“high 

hazard”). Some enlargements are allowed. 

New buildings are allowed according to 

city development plan. 

• Fs-Area with Stabilized Landslides 

(“medium-moderate hazard”). The 

development of these areas is indicated in 

the city development plan. 

The catastrophic event of May 1998, which caused 

heavy damages and victims in municipalities 

of Sarno and Quindici (Campania), urged the 

Fig. 1: Example of Atlas of Landslides published by Po River Basin Authority (elaboration by Arpa Piemonte). 

Abb. 1: Beispiel des „Atlas of Landslides“ (Bergsturz-Atlas), veröffentlicht von Po River Basin Authority (Ausarbeitung von ARPA 

Piemonte). 

government to give answers for development 

regulation (to reduce or eliminate landslides 

losses). According to the national Law n. 

267/1998, the government enforced legislative 

measures at the national level, including the 

procedure to define landslide risk areas. 

Another important aspect of the 

Law n. 267/1998 regards the development of 

“extraordinary plans” to manage the situations of 

higher risk (R.M.E.-Aree a Rischio Molto Elevato), 

where safety problems or functional damages 

are possible. Local and regional authorities 

are obliged to define, design and apply proper 

measures to risk mitigation, with national funding. 

In Piedmont, these actions have been applied in 

some significant cases such as in Ceppo Morelli 

(Valle Anzasca in northern part of Piemonte), 

classified as a very high-risky area. 

Low Level Legislation (Local Urban Development Plan) 

The classification of areas made by the Po Basin 

Authority is a binding act. The municipality must 

adopt a new town development plan taking into 

account that classification. If the municipality 

wants to change PAI classification, a deep analysis 

of the areas has to be done to justify new land use 

destination. 

Regione Piemonte Regional Law for 

Urban Development L.R. n. 56/1977, which is the 

main legal instrument of land use management at 

a local scale, as well as the Regional Law L.R. n. 

45/1989 which regulates land use modification 

and transformation in areas subject to 

environmental protection, divides areas in more 

detailed classes having (almost) same meaning of 

PAI classification. 

In Piemonte, the local management plan 

(required by the Regional Law L.R. n. 56/1977) 

includes the danger/hazard zoning in order 

to identify landslide prone areas on the basis 

of geological and morphological features and 

historical analysis. 

In a state of emergency (as established by 

the Regional Law n. 38/1978, which regulate and 

organise interventions related to severe instability 

phenomena), a specific article of the regional law 

56/1977 (art. 9/bis) allows inhibiting or suspending 

development in the involved areas. Consequently, 

new land-use planning must be realised (upgrade/ 

revision of the local management plan). 

The last integrations to this law 

(Circolare del Presidente della Giunta Regionale, 

n. 7/LAP/1996 and Nota Tecnica Esplicativa, n. 

12/1999) introduced the concept of hazard and 

risk zoning, classifying the whole territory in 

different classes where land uses are precisely 

regulated and defined, where building is 

forbidden, where preventive measures have to be 

taken, etc… 

It is important to clarify that Regione 

Piemonte does not have an official regional 

Geological Survey. Some geological functions 

are executed by Arpa Piemonte (Agency 

for Environmental Protection) having two 

“geological” departments: one dedicated to 

Geological Informative System, research and 

applied projects, the other one deals with 

geological aspects of municipality urban plans. 

Therefore, we produce landslide danger, 

hazard and risk analyses that have not any legal 

consequences. 

Within many regional, national and 

European projects, Arpa Piemonte carried 

out many experiences in fields of assessing 

methodology for landslides hazard assessment: 

for instance, the IMIRILAND Project within Fifth 

Framework Programme, Interreg PROVIALP 

Project Fall or national Project of Geological 

Cartography for shallow and planar landslides 

hazard maps in the southern hilly part of Piemonte 

region called Langhe (fig. 2).


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So complete coverage of basic information is 

available (lithology, geotechnical geo-database, 

landslides inventory, etc…), but only few rigorous 

applications of hazard & risk assessment. 

One of the available tools produced 

by Arpa Piemonte is the regional part of Italian 

Landslides Inventory (IFFI). It is a national program 

of landslide inventory, sponsored by national 

Fig. 3: Arpa Piemonte Web-GIS Information Service of the IFFI Project. 

Abb. 3: ARPA Piemonte, Web-GIS Informationsdienst des IFFI-Projekts. 

Fig. 2: Extract from the 

shallow landslides hazard 

map of 1:50,000 scale sheet 

Dego in Piemonte. The 

traffic light colors indicate 

increasing hazard (from 

green to red), referring to 

return periods of critical 

rainfall (Arpa Piemonte, 

2006). 

Abb. 2: Auszug aus dem 

Gefahrenzonenplan rutschgefährdeter, 

oberflächennaher 

Hänge im Maßstab 

von 1:50.000 Dego im 

Piemont. Die Ampelfarben 

veranschaulichen die 

zunehmende Gefahr (von 

grün zu rot) mit Bezug auf 

Wiederkehrdauern kritischen 

Niederschlags (ARPA 

Piemonte, 2006). 

authorities and made locally by the regions. It 

is the first try of an inventory based on common 

graphical legend and glossary. 

In Piemonte, over 35,000 landslides 

were recognized by interpreting aerial photos 

and field surveys and the Informative System of 

Landslides is constantly updated with inclusion of 

new landslides or corrections and deepening of 

existing landslides (fig. 3). Every region decided 

by itself if the results of IFFI Project (danger maps) 

do or do not have or a legal value. Currently, in 

Piemonte landslides inventory coming from IFFI 

Project is not a legal basis but it is one of the tools 

available that can be consulted. 

In any event, IFFI represents a very 

important tool for the planners who finally have 

the first homogeneous, shared, detailed and most 

complete knowledge of the landslide occurrence 

on the whole territory. 

As a general remark for Italy, it has 

to be observed that public legislation defines 

general principles and lines of conduct, functions, 

activities and authorities involved, while the 

regional administrations apply restrictions on land 

use through different regional laws. 

Final remarks 

• Laws or rules that indicate how a landslide 

analysis (danger, hazard, risk) has to be 

done, do not exist; 

• There is often some confusion among 

danger, hazard and risk. An inventory 

map can be used as hazard map (i.e. 

susceptibility map), without any prevision 

of scenarios; 

• There is some lack of trust in quantitative 

methods. Qualitative approach seems to be 

preferred; 

The technicians who make the maps have to 

think firstly: 

• Who will be the end users? 

• What will be the use of maps? 

• Is the scale of work suitable for this? 

• Are the complexity of methods (time, 

resources, needed input data…) and 

results appropriate and understandable for 

decision makers? 


Stefano Campus 

Arpa Piemonte 

Dipartimento Tematico Geologia e Dissesto 

via Pio VII 9, 10135 TORINO (ITALY) 

stefano.campus@regione.piemonte.it 


ARPA PIEMONTE, (2006), 

Note illustrative della Carta della Pericolosità per Instabilità dei Versanti 

alla scala 1:50,000 Foglio n. 211 Dego. (S. Campus, F. Forlati & G. Nicolò 

editors), Apat, Roma. (in Italian); 


Evaluation and prevention of natural risks. (S. Campus, F. Forlati, S. Barbero 

& S. Bovo editors), Balkema Publisher; 


Interreg IIIa 2000-2006 Alpi Latine Alcotra. Progetto n. 165 PROVIALP- 

Protezione della Viabilità Alpina. Final Report (in Italian); 


Geographic Information System on-line - http://webgis.arpa.piemonte.it 

V.A. (2004), 

Identification and mitigation of large landslides risks in Europe. The 

IMIRILAND project. (C. Bonnard, F. Forlati & C. Scavia editors), Balkema 

Publisher;


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Seite 109 


Slowenien liegt in einem komplexen Raum Adria – Dinaren – Pannonisches Becken, und 

seine allgemeine geologische Struktur ist bestens bekannt. Aufgrund seiner außerordentlich 

heterogenen geologischen Lage ist Slowenien Hangmassenbewegungen (SMM = slope mass 

movement) sehr stark ausgesetzt. Die slowenische Gesetzgebung (und darauf beruhend auch 

die entsprechenden Maßnahmen) sind vorwiegend auf die Schadenbehebungsphase und die 

Begrenzung der Auswirkungen bereits aufgetretener SMM-Vorkommnisse ausgerichtet, es mangelt 

jedoch an vorbeugenden Maßnahmen. Der Zweck dieses Artikels ist die Präsentation von 

Gefahrenhinweiskarten über Hangmassenbewegungen auf nationaler und regionaler Ebene, 

die zum Schutz vor schnellen Massenbewegungen in Slowenien erstellt wurden und die eine 

fachlich fundierte Grundlage für die entsprechenden Präventivmaßnahmen bilden. Der nächste 

logische Schritt wäre, dieses Know-how und diese Ansätze in die Gesetzgebung zu integrieren. 

Schlüsselwörter: Massenbewegungen, Gesetzgebung, Gefahrenhinweiskarte, Slowenien 

MARKO KOMAC, MATEJA JEMEC 


Rapid Mass Movements in Slovenia 

Standards und Methoden der Gefährdungsanalyse für 

schnelle Massenbewegungen in Slowenien 

Summary: 

Slovenia is situated on the complex Adria – Dinaridic – Pannonian structural junction and 

its general geological structure is well known. As a consequence of an extraordinarily 

heterogeneous geological setting, Slovenia is highly exposed to slope mass-movement 

processes. While Slovenian legislation (and based on that also measures) mainly focuses on 

the remediation phase and mitigation of consequences of SMM events that have already 

occurred, its biggest deficiency lays in the area of prevention measures. The purpose of this 

paper is to represent slope mass movement susceptibility maps on a national and a local 

level that have been developed for protection from rapid mass movements in Slovenia and 

which form an expert foundation for the prevention measures. The next logical step would be 

to incorporate this knowledge and approach into legislation. 

Keywords: mass movement processes, legislation, susceptibility map, Slovenia 

but they can be mitigated or avoided, applying 


adequate legislation measures supported by 

corresponding expert argumentation. Although 

Slovenian territory occupies the Eastern flank of Slovenian legislation (and hence also measures) 

the Alpine chain. As in other areas of the Alpine mainly focuses on the remediation phase and 

region, Slovenia is exposed to different slope mass mitigation of consequences of SMM events that 

movements (SMM) above the average of the rest of have already occurred, it’s biggest deficiency lays 

Europe. SMM that represent substantial problems in the area of prevention measures. While, in the 

can be generally divided into three groups, 1) case of rare SMM events, the current approach of 

landslides, 2) debris-flows, and 3) rock falls. The exclusively post-event measures is conditionally 

majority of SMM events cannot be prevented, sustainable, in the case of frequent events it 

Fig 1: Relation between hazards on one side and elements at risk on the other, and the risk in between (after Alexander, 2002). 

Abb. 1: Beziehung zwischen Gefahren und gefährdeten Elementen, und das dazwischen liegende Risiko (nach Alexander, 2002).


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Seite 111 

becomes unsustainable and brings a huge burden 

to the local, regional and state budget. The only 

reasonable approach would hence be minimising 

interaction between SMM events and elements 

at risk. Graphically this interaction would be 

presented as a cross-section between the natural 

hazard on one side and vulnerability of elements 

at risk on other side (Fig 1). 

2. Legislation in the field of slope mass movement 

domain 

In the area of systematic prevention measures 

regarding SMM, Slovenia lags behind other Alpine 

countries or regions. One of the basic approaches 

to solve the problem is to establish potentially 

hazardous areas due to natural phenomena and 

the inclusion of this information in spatial plans. 

Information on geology, upon which the slope 

mass movement occurrence heavily depends, it is 

not yet an integral part of spatial plans. Legislative 

acts deal mostly with remediation issues instead 

with the prevention measures. 

The protection strategy against landslides 

(within legislation the term landslide also other 

types of slope mass movements are included) 

varies substantially and is tailored according 

to different terrain conditions. They are mainly 

divided into prevention, emergency protective 

measures and permanent measures adopted in the 

process for remediation. In the frame of preventive 

actions, the emphasis is on creating a national 

database of active landslides (and other SMM) and 

intentions of government to include hazards doe 

to landslides into spatial planning. In the planning 

and implementation of emergency protective 

measures, the emphasis is on protecting human 

lives and property. 

Law on protection against natural and other disasters 

(Official Gazette of RS, no. 64/94) 

The Act governs the protection against natural 

and other disasters and includes the protection of 

people, animals, property, cultural heritage and 

environment against any hazard or accidents (risk) 

that can threaten their safety. The main goal of 

the protection against natural and other disasters 

system is to reduce the number of disasters, and 

to forestall or reduce the number of victims and 

other consequences of disaster. The basic tasks 

of the system are: prevention, preparedness, 

and protection against threats, rescue and help, 

providing of basic conditions for life, and recovery. 

National program of protection against natural and other 

disasters (Official Gazette of RS, no. 44/02) 

On the basis of the Resolution, the National 

Programme of Protection against Natural and 

Other Disasters for the period 2002 – 2007. 

The National Programme is oriented towards 

the prevention and its basic aim is to reduce the 

number of accidents and to prevent or minimise 

its consequences. 

Law on the Remediation of consequences of natural 

disasters (Official Gazette of RS, no. 114/05) 

The Act defines a landslide as a natural disaster. 

According to the article 11, with some restriction 

and at some level of damage, state budget funds 

may be used to ease the effects of natural disasters. 

Damage assessment is made in accordance 

with the Regulation on the methodology for 

damage assessment (Official Gazette of RS, 

no. 67/03, 79/04), after which the landslide is 

considered a landslide, which threats a property 

or infrastructure. 

Water Act (Official Gazette RS, no. 67/02, 4/09) 

Protection against the harmful effects of water 

that is among other the issues dealt with this 

act also refers to protection against landslides. 

Threatened area is defined by Government, which 

is responsible for protecting the population, 

property and land in dangerous exposed areas. 

In order to protect against the harmful effects of 

water, land in the threatened area is categorized 

into classes based on the risk. 

Act on measures to eliminate the consequences of certain 

large-scale landslides in 2000 and 2001 (Official Gazette 

RS, no. 21/02, 92/03, 98/05) 

Act defines the format and the method of 

financing and form of allocating state aid for 

the implementation of remedial measures, to 

prevent the spread of landslide and stabilization 

of landslides on the specific area of influence. It 

covers several major landslides in Slovenia. 

Spatial Development Strategy of Slovenia (Official Gazette 

of RS, no. 76/04) 

The Spatial Development Strategy of Slovenia is a 

public document guiding development in the field 

of landslide problematics. It provides a framework 

for spatial development throughout the country 

and sets guidelines for development in European 

space. It provides for the creation of spatial 

planning, its use and conservation. The spatial 

strategy takes into account social, economic and 

environmental factors of spatial development. 

Slovenia's Development Strategy 

Slovenia's Development Strategy sets out the 

vision and objectives of Slovenia and five 

development priorities with action plans. The 

chapter on protection against natural disasters is 

included in the fifth development priority, which 

is designed to achieve sustainable development. 

Regulation of the spatial order of Slovenia (Official Gazette 

of RS, no. 122/04) 

Regulation of spatial order in Slovenia provides 

the rules for managing the field of landslide 

problematic. One of the important articles is 

Article 67, in which is mentioned how to plan 

according to the limitations which are caused by 

natural disasters and water protection. 

Resolution of the National Environmental Act (Official 

Gazette of RS, no. 2/06) 

The National Environmental Action Programme 

(NEAP) is the basic strategic document in the 

field of environmental protection, aimed at 

improving the overall environment and quality 

of life and protection of natural resources. NEAP 

was prepared under the Environmental Protection 

Act and complies with the European Community 

Environment Programme, which addresses the 

key environmental objectives and priorities 

that require leadership from the community. 

The objectives and measures are defined in 

the four areas, namely: climate change, nature 

and biodiversity, quality of life, and waste and 

industrial pollution. 

3. Methodology 

Due to specifics of different slope mass movement 

processes, a single approach would be hampered 

in its results / prognosis. The following chapter 

presents an overview of approaches to slope 

mass movements (1 – landslides; 2 – debris-flows; 

3 – rock falls) hazard assessment. The presented 

approaches are similar to a certain level, they also 

differ according to the scale of the assessment. The


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final results (but not the only ones) of approaches 

presented in the following text were presented 

in a form of warning maps that are still the main 

product used by end users. All the analyses were 

conducted in GIS, which enables the end users to 

implement results also in a form of databases or a 

digital format. 

According to Skaberne (2001) the 

terminology of slope mass movements in Slovenia 

are as follows: landslides are processes of 

translational or rotational movement of rock or 

soil as a consequence of gravity at discontinuity 

plane(s). Rock falls are processes of falling or 

tumbling of a part of rock or soil along a steep 

slope. Debris-flows are processes of transportation 

of material composed of soil, water and air. 

The landslide susceptibility model for 

Slovenia at scale 1:250,000 was developed 

at the Geological Survey of Slovenia in 2006 

(Komac & Ribičič, 2006). The final result of this 

approach was presented in a form of a warning 

map (Fig. 2). Based on the extensive landslide 

database that was compiled and standardised 

at the national level, and analyses of landslide 

spatial occurrence, a Landslide susceptibility map 

of Slovenia at scale 1 : 250,000 was completed. 

Altogether more than 6,600 landslides were 

included in the national database, of which 

roughly half are on known locations. Of 3,257 

landslides with known locations, random but 

representative 65% were selected and used for 

the univariate statistical analyses (χ2) to analyse 

the landslide occurrence in relation to the 

spatio-temporal precondition factors (lithology, 

slope inclination, slope curvature, slope aspect, 

distance to geological boundaries, distance to 

structural elements, distance to surface waters, 

flow length, and land cover type) and in relation 

to the triggering factors (maximum 24-h rainfall, 

average annual rainfall intensity, and peak ground 

acceleration). The analyses were conducted using 

GIS in raster format with a 25 × 25 m pixel size. 

Five groups of lithological units were defined, 

ranging from small to high landslide susceptibility. 

Furthermore, critical slopes for the landslide 

occurrence, other terrain properties and land cover 

types that are more susceptible to landsliding were 

also defined. Among triggering factors, critical 

rainfall and peak ground acceleration quantities 

were defined. These results were later used as 

a basis for the development of the weighted 

linear susceptibility model where several models 

with various factor weights variations based on 

previous research were developed. The rest of 

the landslide population (35 %) was used for the 

model validation. The results showed that relevant 

precondition spatio-temporal factors for landslide 

occurrence are (with their weight in linear model): 

lithology (0.3), slope inclination (0.25), land cover 

type (0.25), slope curvature (0.1), distance to 

structural elements (0.05), and slope aspect (0.05). 

Beside landslide susceptibility 

assessment, a rainfall influence on landslide 

occurrence was analysed since rainfall plays 

an important role in the landslide triggering 

processes. Analyses of landslide occurrences in 

the area of Slovenia have shown that areas where 

intensive rainstorms occur (maximal daily rainfall 

for a 100-year period), and where the geo-logical 

settings are favourable an abundance of landslide 

can be expected. This clearly indicates the spatial 

and temporal dependence of landslide occurrence 

upon the intensive rainfall. Regarding the landslide 

occurrence, the intensity of maximal daily and 

average annual rainfall for the 30 years period 

was analysed. Results have shown that daily 

rainfall intensity, which significantly influences the 

triggering of landslides, ranges from 100 to 150 

mm, most probably above 130 mm. Despite the 

vague influence, if any at all, of the average annual 

rainfall, the threshold above which significant 

number of landslides occurs is 1000 mm. 

Fig. 2: Landslide susceptibility warning map of Slovenia at scale 1:250,000 (Komac & Ribičič, 2006, 2008). 

Abb. 2: Gefahrenhinweiskarte für Rutschungen in Slowenien im Maßstab von 1:250.000 (Komac & Ribičič, 2006, 2008). 

The debris-flow susceptibility model for Slovenia weighted sum approach was selected on the 

at scale 1:250,000 was also developed at basis of easily acquired spatio-temporal factors to 

Geological Survey of Slovenia in 2009 (Komac et simplify the approach and to make the approach 

al., 2009). The final result of this approach was easily transferable to other regions. Based on the 

presented in a form of a warning map (Fig. 3). calculations of 672 linear models with different 

For the area of Slovenia (20,000 km 2 ), a debrisflow 

susceptibility model at scale 1:250,000 was factors and based on results of their success to 

weight combinations for used spatio-temporal 

produced. To calculate the susceptibility to debrisflow, 

occurrences using GIS several information factors’ weight combination was selected. To avoid 

predict debris-flow susceptible areas, the best 

layers were used such as geology (lithology and over-fitting of the prediction model, an average of 

distance from structural elements), intensive weights from the first hundred models was chosen 

rainfall (48-hour rainfall intensity), derivates of as an ideal combination of factor weights. For 

digital elevation model (slope, curvature, energy this model an error interval was also calculated. 

potential related to elevation), hydraulic network A debris-flow susceptibility model at scale 

(distance to surface waters, energy potential of 1:250,000 represent a basis for spatial prediction 

streams), and locations of sixteen known debris of the debris-flow triggering and transport areas. It 

flows, which were used for the debris-flow also gives a general overview of susceptible areas 

susceptibility models’ evaluation. A linear model- 

in Slovenia and gives guidance for more detailed


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(4) Mapping of problematic areas at scale 

1:5000 or 1:10,000 for the purpose of the 

highest detail planning 

(3) Development of detailed 

geohazard map at scale 1:25,000 as 

a combination of synthesis of 

phases (1) and (2) 

(1) Synthesis of archive geological data into the 

overview geohazard map at scale 1:25,000 

(2) Development of statistical geohazard at scale 

1:25,000 

Fig. 3: Debris-flow susceptibility warning map of Slovenia at scale 1:250,000 (Komac et al., 2009). 

Abb. 3: Muren-Gefahrenhinweiskarte Sloweniens im Maßstab von 1:250.000 (Komac et al., 2009). 

research areas and further spatial and numerical 

analyses. The results showed that approximately 

4% of Slovenia’s area is extremely high susceptible 

and approximately 11% of Slovenia’s area of 

processes, taking the Bovec municipality as 

the case study area. The geohazard map at the 

scale 1:25,000 as the final product is aimed 

to be directly applicable in spatial planning 

susceptibility to debris-flows is high. As expected, of local communities (municipalities). The 

these areas are related to mountainous terrain in 

the NW and N of Slovenia. 

In the frame of a research project, slope 

mass movement geohazard estimation – The 

Bovec municipality case study an approach to 

assess the landslide and rock-fall susceptibility at 

the municipal scale (1:25,000) (Bavec et al, 2005; 

Komac, 2005). The production of a susceptibility 

map that should represent (officially not included 

among the documentation yet) one of basic layers 

in the spatial planning process shown in the Fig. 4. 

Methodology was developed for estimation 

of geohazard induced by mass movement 

requirements that were followed to achieve this 

aim were: expert correctness, reasonable time of 

elaboration, and easy to read product. Elaboration 

of the final product comprises four consecutive 

phases, of which the first three are done in the 

office: 1) synthesis of archive data, 2) probabilistic 

model of geohazard induced by mass movement 

processes, 3) compilation of phases 1 and 2 into 

the final map at scale 1:25,000. As the last phase, 

field reconnaissance of most hazardous areas is 

foreseen. The susceptibility model development 

was based on the upgrading of the expert geohazard 

map at scale 1:25,000 with a probabilistic model 

Fig. 4: Schematic diagram of the process of production of landslide and rock-fall susceptibility at the municipal scale (1:25.000) 

(Bavec et al., 2005). 

Abb. 4: Schematische Darstellung der Erstellung von Gefahrenhinweiskarten über Erdrutsch, Berg- und Felssturz im Maßstab einer 

Wanderkarte (1:25.000) (Bavec et al., 2005). 

development that included relevant influence 

factors. For analytical purposes, 10,816 models 

were developed: 3,142 for landslide susceptibility 

and 7,674 for rock-fall susceptibility. In both 

cases, geology/lithology and slope angle showed 

to be the most important influencing factors. 

Regarding landslides, additional important factors 

were land use and synchronism of strata bedding 

and slope aspect, and in the case of rock-falls an 

additional important factor was synchronism of 

strata bedding and slope aspect. 

The methodology is focused towards 

the direct use of the final product in the process 

of spatial planning at the municipal level and is 

divided into four phases as shown in Fig. 4: 

• (1) Synthesis of archive geological data 

in the overview geohazard map at scale 

1:25,000 (Budkovič, 2002). 

• (2) Development of statistical geohazard at 

scale 1:25,000 (Komac, 2005). 

• (3) Development of detailed geohazard 

map at scale 1:25,000 as a combination of 

synthesis geological map (1) and statistical 

geological model (2) and delineating the 

most problematic areas. 

• (4) Mapping of problematic areas at scale 

1:5,000 or 1:10,000 for the purpose of the 

highest detail planning. 

All presented approaches are based on a probability 

statistical model that is a part of a conceptual 

development model of general or detailed slope 

mass susceptibility maps represented in Fig 5.


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Univariate analysis (x 2 ) 

of SMM occurrence by 

classes within each of 

the influence factor 

Field testing 

Good results 

Development of 

phenomenon 

susceptibility map 

Influence factors classes 

ranging based upon 

their influence on the 

SMM occurrence 

Bad results 

Selection of optimal 

and most logical 

susceptibility model 

Values normalisation 

within each influence 

factor (0-1) 

Testing of different 

models developed on 

the weighted sum 

of influence factors 

Fig 5: Conceptual 

model of 

development 

of general or 

detailed slope 

mass susceptibility 

maps. 

Abb. 5: 

Konzeptionelles 

Modell für die 

Entwicklung von 

allgemeinen 

oder detaillierten 

Gefahrenhinweiskarten 

über 

Hangbewegungen. 

Marko Komac 

Dimiceva ulica 14 

1000 Ljubljana 

SI-Slovenia 

Marko.komac@geo-zs.si 

Mateja Jemec 

Dimiceva ulica 14 

1000 Ljubljana 

SI-Slovenia 

Mateja.jemec@geo-zs.si 

ALEXANDER, D.E., 2002. 

Principles of emergency planning and management. Oxford University 

Press, New York, 340 pp. 

BAVEC, M., BUDKOVIČ, T. AND KOMAC, M., 2005. Estimation of 

geohazard induced by mass movement processes. The Bovec municipality 

case study. Geologija, 48/2, 303-310. 

BUDKOVIČ, T., 2002. Geo-hazard map of the municipality of Bovec. 

Ujma, 16, 141-145. 

KOMAC, M. 2005. Probabilistic model of slope mass movement 

susceptibility - a case study of Bovec municipality, Slovenia. Geologija, 

48/2, 311-340. 

KOMAC, M., RIBIČIČ, M., 2006. Landslide susceptibility map of Slovenia 

at scale 1:250,000. Geologija, 49/2, 295-309. 

KOMAC, M., KUMELJ, Š. AND RIBIČIČ, M., 2009. 

Debris-flow susceptibility model of Slovenia at scale 1: 250,000. Geologija, 

52/1, 87-104. 

SKABERNE, D., 2001. 

Prispevek k slovenskemu izrazoslovju za pobočna premikanja. Ujma, 

14–15, 454–458. 

For all influence factors included in the weighted 

sum model calculation, original values were 

transformed into the same scale, which ranged 

from 0 – 1 to assure the equality of the input data. 

In other words, within each factor original values 

were normalised with the eq. 1. 

(RV - Min) 

NVR = , 

Max - Min 

eq. 1 

or discreet variable value. Final slope mass 

movements susceptibility values (the range 

is between 0 and 1) were classified into 6 

susceptibility classes: 0 – Negligible (or None); 1 

– Insignificant (or Very Low); 2 – Low; 3 – Medium 

(or Moderate); 4 – High; 5 – Very High. 

4. Conclusion 

Where NVR represents new and normalised 

value, and RV the old (nominal) value. Min and 

Max represent the minimum and maximum 

original value within the factor, respectfully. For 

the purpose of the development of the best and 

at the same time the most logical susceptibility 

model, a weighted sum approach (Voogd, 1983) 

was used (eq. 2). 

n 

H = ∑ w j 

x f ij 

j=l 

eq. 2. 

Where H represents standardised relative 

phenomenon susceptibility (0 – 1), w j 

represents 

the factor weight, and f ij 

represents a continuous 

Slope mass movement processes are specific in 

their nature, hence separate analyses had to be 

performed and a different model development 

had to be developed. In Slovenia, slope mass 

movement susceptibility maps have been 

developed on national and on local level. In the 

case of the latter, which has an actual application, 

value maps were developed only for some test 

areas. Thus several questions remain open and 

these are: when will the geohazard layer be 

included as a compulsory part of the spatial 

planning document, to what extent quality 

geological data will be used for the assessment, 

and how the lack of detailed geological data 

would be tackled.


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KARL MAYER, ANDREAS VON POSCHINGER 


Geological Dangers (Mass Movements) in Bavaria 

Standards und Methoden zur Verminderung 

von geologischen Gefährdungen durch 

Massenbewegungen in Bayern 

Summary: 

Information about geological hazards in the Bavarian Alps (e.g. rock falls, landslides) is 

available in the Internet or intranet section Georisk of the Bodeninformationssystem Bayern 

(BIS-BY) (www.bis.bayern.de). This information system is already used by a number of 

departments such as district administrations, water and traffic management offices, forest 

management as well as private users. By now the BIS-BY only shows the sites of origin of 

geological hazards and not the whole endangered area, which would be relevant for land 

use planning. This area, the so called process area, can only be defined by empirical or 

numerical simulations and models. 

A hazard map gives an overview of the situation. It is based on model calculations and 

empirical analysis and can be verified by the Georisk-cadastre (BIS-BY). Concerning the 

spatial extent of the process areas, possible inaccuracies may impair an exact expression 

of the danger. The hazard map shows large areas where a special type of danger can be 

assumed. Therefore, will be easier to deduce possible conflicts between hazards and land 

use. Hazard maps can be included in the land development plan or can be used to assign 

priorities while taking measures. 


Informationen über geogene Gefährdungen (z.B. Steinschlag, Felsstürze, Rutschungen) sind 

als GEORISK-Daten über das Bodeninformationssystem Bayern (BIS-BY) im Internet oder 

Intranet abrufbar (www.bis.bayern.de). Dieses Informationssystem wird bereits von vielen 

Fachstellen genutzt. Neben den Landkreisen sowie vielen Kommunen sind die Behörden der 

Wasserwirtschaft, der Straßen- und Forstverwaltung sowie private Planer die Hauptnutzer. Im 

BIS-BY ist bisher allerdings nur das Herkunftsgebiet von Gefährdungen dargestellt, nicht der 

planungsrelevante Gefährdungsbereich. Dieser kann nur durch empirische oder numerische 

Simulationen und Modellierungen abgegrenzt werden. 

Die Gefahrenhinweiskarte gibt eine Übersicht über die Gefährdungssituation. Sie basiert 

sowohl auf Modellrechnungen als auch auf empirischen Untersuchungen und wird mit dem 

GEORISK-Ereigniskataster (BIS-BY) auf Plausibilität geprüft. Bezüglich der räumlichen Abgrenzung 

kann sie Ungenauigkeiten enthalten und die Gefährdung nicht in jedem Fall genau 

wiedergeben. Die Gefahrenhinweiskarte hält für große Gebiete flächendeckend fest, wo 

mit welchen Gefahren gerechnet werden muss. Daraus lassen sich mit geringem Aufwand 

mögliche Konfliktstellen zwischen Gefahr und Nutzung ableiten. Die Gefahrenhinweiskarten 

können einerseits in Flächennutzungspläne mit einfließen und dienen anderseits zur Prioritätensetzung 

beim Erarbeiten weitergehender Maßnahmen. 


In Germany, geogenic natural hazards, such 

as mass movements, karstification, large scale 

flooding as well as ground subsidence and uplift 

affecting building ground, shall be recorded, 

assessed and spatially represented using a common 

minimal standard in the future. For this purpose, 

the “Geohazards” team of engineering geologists 

of the different German federal governmental 

departments of geology (SGD) are giving 

recommendations on how to create a hazard map. 

These recommendations of minimum requirements 

are directed at the employees of the SGD. An 

important component for developing hazard maps 

is the construction and evaluation of landslide 

inventories (e.g. landslide or sinkhole inventories). 

The recorded data in the inventories 

should have a minimal nationwide standard and 

are divided into: 

• Main data of the topic mass movements and 

subrosion / karst with information about the 

spatial positioning, about determination of 

coordinates, etc. 

• Commonly shared technical data of the 

subject mass movements and subrosion / 

karst with information about the date 

of origin, about the land use and about 

damage, etc. 

• Specific technical data of the subject mass 

movement and subrosion / karst 

• Data concerning subsidence and uplift 

Computerized modelling increasingly allows 

the identification of hazard areas that have been 

verified using the landslide inventory or through 

evaluation of the results of field work. The 

current emphasis in Germany is on hydrological 

modelling of flood events that are used for 

water management issues in flood prevention. 

Geotechnical modelling is used increasingly for 

rock falls, avalanches and shallow landslides.


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If necessary, in addition to the tools described 

above, field studies will be needed for exact 

clarification and assessment of given situations. 

In Alpine regions, natural hazards are 

a common phenomenon. Landslides, rock falls 

and mudflows occur in the course of mountain 

degradation that reflects the natural slope 

instability of mountain areas. Landslides are mostly 

triggered by extreme rainfall that will, according 

to climate scientists, become more relevant in 

Alpine regions in particular (Umweltbundesamt 

2008). With an increase in heavy rainfall events 

an increase in landslide events must be expected. 

With approximately 4450 km², the 

Bavarian Alps cover about 6.3 % of Bavaria. The 

Bavarian Alps are the most important tourist region 

of Bavaria and, therefore, of particular importance. 

Furthermore, they have a unique ecological value 

that has to be specially protected. Since it is more 

and more difficult to ensure this protection by 

structural activities, protective measures need 

to be involved in the planning process and also 

allow sustainable and cost effective strategies. 

The most effective and sustainable 

method to prevent losses arising from hazardous 

events is to avoid land use in the endangered 

areas. In areas where construction already has 

been established or where construction of new 

infrastructure or buildings is unavoidable, it 

is essential to determine areas endangered by 

geological hazards. 

In May 2008, the Bavarian Environmental 

Agency launched the project hazard map for the 

Bavarian Alps. The aim of the project is to create 

a hazard map for deep seated landslides, shallow 

landslides and rock fall areas for the whole of 

the Bavarian Alps. It will be finished during 

December 2011. 

2. Definition of a hazard map 

The federal geological surveys of Germany 

agreed on definitions for the terminology used 

for mapping of geological hazards (Personenkreis 

“Geogefahren” 2008) based on BUWAL (2005). A 

hazard map gives a first overview of areas affected 

by landslides (potentially endangered area) and 

can be a basis for the detection of conflicts of 

interests. By defining a most probable design 

event and integrating it in the landslide modelling 

process, a hazard map also gives a qualitative 

statement about the probability of a landslide 

event. The potential process areas of the expected 

landslides vary depending on the design event, 

the geological, topographical and morphological 

situation and the existence of forest. Modelling 

parameters for rock fall and shallow landslide 

simulations can be deduced and trivialised from 

comprehensive data. 

Generally the scale of a hazard map 

ranges from 1:10,000 to 1:50,000. Within this 

project, despite the possibilities of the zoom 

function of a GIS, the hazard map is produced for 

a scale of 1:25,000. 

3. Material and methods 

3.1 Basis maps 

Essential data basis for modelling the hazard map 

is a high resolution digital elevation model (DEM) 

derived from airborne laser scanning. The datasets 

are used in different resolutions (1 m, 5 m, 10 m) 

depending on the modelling approach. The 

vertical resolution is better +/- 0.3 m, except for 

very few areas where currently no laser scanning 

data is available. 

3.2 Basis data for landslide modelling 

Information about geological hazards such as 

landslides, rock falls and earth falls, especially 

in the densely populated areas in the Bavarian 

Alps, is available in the section Georisk of 

the Bodeninformationssystem Bayern (BIS-BY, 

www.bis.bayern.de), a GIS-based inventory of 

Bavaria including numerous geological data. By 

now (October 2010), about 4,500 landslide events 

have been detected and evaluated within the 

project area. Every event is described concerning 

its process type and dimension, the age and 

potential future trend of the landslide as well as 

annotations about the source and the degree of 

information. Origin and accumulation zones of 

landslides have been digitised and stored as well 

as significant photos. With all of this the BIS-BY is 

the most important source of information. 

Also integrated in the BIS-BY are maps 

of active areas that have been mapped by field 

work, aerial photo analysis and archive data for 

the main settlement areas. Within these maps 

landslides are classified into four levels of activity 

to give an indirect statement about the level of 

danger. These maps can be used to estimate the 

extension of deep-seated landslides, for example. 

Above all, results of two other projects 

have been used: Within the project HANG 

(historical analysis of alpine hazards), historical 

data of landslides have been evaluated and 

digitised. Within the project EGAR (catchment 

areas in alpine regions), the risk potential of 

alpine torrents has been estimated analysing the 

discharge and catchment potential. 

4. Fall processes 

4.1 Minimum requirements in Germany 

In many states of Germany, only medium to long 

term, large-scale numeric modelling of rock 

fall hazards are possible using high resolution 

terrain models and specialised software. In the 

first stage, a “black and white map” is created 

showing verified / potential rock fall areas derived 

from the landslide inventories and / or remote 

sensing (DEM). This map shows verified as well 

as potential rock fall escarpments i.e. slopes with 

an inclination > 45° (in Alpine areas). The entire 

process area is, however, not depicted. 

In the second stage, the run-out zone, i.e. 

the entire process area, is depicted. That means 

areas prone to rock falls due to the inclination, but 

which are not confirmed. To define these areas, 

estimated empiric angle methods or physical 

deterministic models can be used. 

To determine rock fall escarpments, the 

shadow angle and the geometric slope angle is 

applied. Both the shadow angle (e.g. 27°) as well 

as the geometric slope angle (e.g. 32°) can be 

used as the estimated angle (Mayer & Poschinger 

2005). An angle of deflection from the vertical 

slope can be used as a lateral boundary of the 

process area (e.g. 30°). 

In Bavaria this method is used for 

huge rock masses. For single blocks, a physical 

trajectory model from Zinggeler + GEOTEST is 

used (MAYER 2010). 

4.2 Modelling rock fall of single blocks (methods use in 

Bavaria) 

For the detection of potential starting zones of 

rock falls, two empirical approaches can be 

applied. In a first step, potential starting zones


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stored in the BIS-BY are extracted. These starting 

zones are detected by field work. In areas where 

no information is available, an even more empiric 

approach must be applied: it has to be assumed 

that every slope steeper than 45° is a potential 

detachment zone (Wadge et al. 1993). 

Fig. 1: Basic processes during rock fall simulation (Krummenacher 

et al. 2005). 

Abb. 1: Schematische Darstellung der prinzipiellen Prozesse 

der Steinschlagmodellierung (Krummenacher et al. 2005). 

According to Meißl (1998) or Hegg & 

Kienholz (1995) the process model can be divided 

into two parts: the trajectory model calculating 

the paths of the blocks as vectors and the friction 

model calculating the energy along these paths 

as well as the run-out length. In this project, the 

vector based simulation model of Zinggeler & 

GEOTEST (Krummenacher et al. 2005) is used. 

Beside the topographical information derived from 

the DEM, damping and friction characteristics of 

the slope surface and the vegetation have to be 

known. Furthermore it is very important to define 

a design event for rock fall. That means that, 

according to the geology, form and dimension of 

typical blocks have to be determined. 

As the block dimension is the only 

variable parameter within the simulation, it plays 

an essential role in the calculation of the run- out 

zone. To assess the design events, the starting zones 

already determined within the disposition model 

have been intersected with the geological map. 

The affected geological units have been checked 

by field work. As a result, a mean block size and 

geometry that represents the most probable event 

has been determined for every geological unit. 

This design event has been assigned to one of 

four volume classes. For each of these classes the 

mean block mass has been calculated. The block 

mass of a geological unit is an input parameter for 

the simulation. 

The simulation of the block movement 

is carried out according to physical principles of 

mechanics and is separated into falling, bouncing 

and rolling (Fig. 1). The calculation is a succession 

of these processes with intermediate contacts to 

underground and tree trunks. 

The loss of energy during tread mat 

is controlled by deformability and surface 

roughness. These parameters have to be deduced 

and trivialised from the basis data of the area to be 

investigated. 

Fig. 2: 3D Trajectories with (red) and without (orange) the 

protecting function of forest. 

Abb. 2: 3D Sturztrajektorien mit (rot) und ohne (orange) 

Berücksichtigung der Schutzfunktion des Waldbestandes. 

The simulation has been run for two 

different scenarios. Within the first scenario, the 

forest with the protecting function of the trees 

has been considered. To simulate a worst-case 

scenario, the forest has not been included in the 

second scenario. 

4.3 Modelling rock fall masses (Bavarian approach) 

The application of the different global 

angles depends on slope morphology. A proper 

The trajectory model for rock fall (chapter 4.2) decision for one global angle model can be 

calculates the reach of single blocks. For the runout 

zone of larger rock fall volumes, an empirical and geometrical slope tangent. If the quotient is 

reached by the quotient of shadow angle tangent 

process model with a worst case approach is used. below 0.88, the shadow angle has to be used. 

Numerous papers (Lied 1977, Onofri & Canadian Otherwise the geometrical slope angle is better 

1979, Evans & Hungr 1993, Wieczorek et al. 1999, suited to describe the maximum run-out zone 

Meißl 1998) show that a global angle method is an (Mayer & von Poschinger 2005). 

appropriate approach to determine the maximum 

Global angles can easily be modelled 

run-out zone of rock fall. Two different global with implemented functionalities of standard 

angles have been applied. The first and more GIS programs. Within the project, the viewshed 

important one is the shadow angle (β in Fig. 3). It is function of Spatial Analyst in ArcGIS has been 

defined as angle between the horizontal line and employed. This function identifies all cells on 

the connecting line from the block with maximum a surface (DEM) that can be seen from selected 

run out and the top of the talus. According to observation points (Fig. 4). There are a number 

Evans & Hungr (1993) a shadow angle of 27° of important attributes of every starting point 

has been assumed. The other global angle is the necessary for the modelling process: the vertical 

geometrical slope angle that spans between the view angle, which is the predefined global angle 

horizontal line and top of detachment zone (α in (Fig. 3), the horizontal view angle that is defined 

Fig. 3). A minimum geometrical slope angle of 30° with 30°, as well as the aspect that can be 

is presumed (Meißl 1998). 

calculated out of the DEM. 

Fig. 3: Global angle models: shadow angle (β) and geometrical slope angle (α) (Meißl 1998, modified). 

Abb. 3: Pauschalgefällemodelle: Schattenwinkel (β) und Geometrisches Gefälle (α), verändert nach Meißl (1998).


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To identify of hazard areas, only important rock 

fall areas with evidence of activity have been 

processed. Due to long-lasting field work, there 

is an excellent overview of the situation within 

the densely populated areas in the Bavarian Alps. 

Beyond those areas it is assumed that all important 

rock fall areas are known. To start the modelling 

process, first the global angle approach has to be 

chosen (shadow angle or geometrical angle). After 

digitizing the starting points and determination of 

necessary attributes, the viewshed modelling with 

ArcGIS can be executed. 

5. Slide processes 

5.1 Minimum requirements in Germany 

In the first stage, landslide inventories, e.g. all 

registered objects and the associated near-surface 

processes, should be visually displayed. That 

means affected by definite indications of active 

and inactive landslides and landslides that have 

already occurred (reactivation or enlargement of 

the landslide area is possible). The areas can be 

found using mapping (registers) or remote sensing 

(DEM) methods. 

Fig. 4: The viewshed function identifies all raster locations to 

be seen from appointed starting points with defined global 

angle. 

Abb. 4: Die Viewshed-Funktion ermittelt alle Bereiche, die 

von festgelegten Startpunkten mit einem definierten Vertikalund 

Horizontalwinkel gesehen werden. 

In the second stage, potential 

landslide areas are determined in addition to 

the verified landslide areas. That means areas 

prone to landslides due to the geological and 

morphological situation and the land use (were 

landslides have not yet taken place). These areas 

can be found by using empirical methods due to 

the geological and morphological circumstances 

and the land usage; alternatively / additionally: 

Visualisation of semi-automatically derived areas 

(cross-over between DEM / geological entity); e.g. 

using an additional signature 

The distinction between shallow and 

deep-seated slides is optional when visualising 

the hazard map. Near-surface landslides of 

a small volume (shallow slides) are either 

separately determined using above procedure or 

are displayed simultaneously alongside the deepseated 

slides. 

5.2 Modelling deep seated landslides 

(methods used in Bavaria) 

Deep-seated landslides are mostly result of the 

activation of predefined failure zones, i.e. by 

long lasting rainfall. Experience shows that they 

can range from about 5 m up to more than 100 

m in depth. To identify areas endangered by deep 

seated landslides, two different approaches have 

been applied. On the one hand, areas showing 

evidence of previous deep-seated landslides, with 

either ongoing activity or a clear probability of 

reactivation, have been evaluated. On the other 

hand, the terrain has been evaluated concerning 

an increased susceptibility for deep-seated 

landslides. 

The locality of the origin of danger (areas 

showing a higher probability for the development 

of a deep seated landslide) has been identified 

within the previously cited disposition model. 

Previous experiences and analysis have 

demonstrated that deep-seated landslides mostly 

occur in areas already affected by landslides 

in the past. For this reason they can be used as 

design events. To detect these areas, information 

about known landslides, extracted from the 

databases listed in chapter 3.2 has to be evaluated. 

Permanent activity or more or less recurrent 

reactivation likely produces enlargement of the 

landslide area identified in the disposition model, 

both the detachment and run-out zone upward 

and downward. 

Since a numeric modelling of deep seated 

landslides is not available for a regional scale, the 

determination of the potential process area has 

to be worked out with empirical methods, taking 

into account the local geology and morphology. 

Under extreme conditions, the process 

area can reach the next ridge, terrace or depression 

in the greater surroundings of the landslide. In the 

case of small-scaled scars in smooth slopes, a margin 

of 20 – 30 m has been added to the detachment 

areas to assess the potential process area. 

To determine the potential run out of an 

active or reactivable landslide, the present runout 

length has been determined by databases, 

hillshades and field work in a first step. If there are 

indications for active movements in the landslide 

toe, it is assumed that the run-out length will 

proceed even further in case of a reactivation. The 

danger area has to be dimensioned according to 

geomorphologic conditions. 

6. Flow processes 

6.1. General approach 

The procedure and depiction of flow processes 

like deep-seated landslides (Talzuschub) is similar 

to the method used for slide processes. Flow 

processes rarely occur in low mountain ranges. 

In the German Alpine area, debris flows are 

more related to water-related hazards and for this 

reason not explained here in detail. 

The deep-seated landslides are handled 

in the same way as the slide processes. The 

process occurring in the run-out zone of shallow 

landslides is also mostly a flow process. To estimate 

this process as disposition model in Bavaria, the 

physical computer model SLIDISP is used. To find 

the run-out zones and to simulate the process, the 

model SLIDEPOT (GEOTEST) is applied. 

6.2 Modelling shallow landslides (methods used in Bavaria) 

Shallow landslides are usually triggered by heavy 

rainfall, depending on the predisposition of the 

slope. Like the rock fall simulation, the modelling 

of shallow landslides is carried out in two steps. 

The starting zones are calculated in the disposition 

model and the run-out zones are calculated in the 

process model. 

For the disposition model, the 

deterministic numerical model SLIDISP (Liener 

2000 and GEOTEST AG) is used. This assumes an 

above average precipitation for a certain area. The 

Infinite-Slope-Analysis is applied to calculate the 

slope stability for every raster cell. Fundamental 

basic data are the slope angle, derived from the DEM 

from which the thickness of soil will be deduced 

and the geology which allows to determine friction 

angle and cohesion as geotechnical parameters. 

The factor of safety F will be calculated for every 

raster cell to describe the ratio of retentive and 

impulsive forces (Fig. 5, Selby 1993). 

The natural range in the variation of 

different input parameters will be considered 

using a Monte-Carlo-Simulation. For every 

raster cell, the number of instable cases will be 

determined. The higher the number of instabilities 

the higher is the probability of slope failure. 

Since the occurrence of forest affects the stability 

in an enormous way, the root strength will be


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influences on karstification, can be noted in an 

additional category. Optionally, a differentiation 

between carbonate, sulphate and chloride 

karstification can be implemented in the first or 

second stage of the hazard map. If the information 

is available in individual states, the spread of the 

inner and outer salt slopes as well as intact salt 

domes should be entered into the hazard map. 

8. Discussion 

Fig. 5: Principle for the calculation of the factor of safety F for every raster cell (Selby 1993). 

Abb. 5: Grundlagen zur Berechnung des Sicherheitsgrades F einer Rasterzelle (Selby 1993). 

integrated in the calculation of the factor of safety angle. The expansion stops if a defined number 

as an additional parameter. Considering the root of expansion steps is achieved or if the calculated 

strength and its effect on soil stability it is possible value falls below a defined threshold. 

to simulate two scenarios with different intensities 

The run-out zones will be calculated for 

of the “root effect” (high and low). 

both scenarios. In both cases, a maximum of 8 

To calculate the run-out zones. the expansion steps have been calculated while the 

raster-based model SLIDEPOT is used (GEOTEST degradation factor has been reduced in the forest. 

AG). For every raster cell in the starting zone, Because of uncertainties concerning complex 

the accumulation will be modelled in the flow edge conditions, the degradation factors have 

direction. The model is based on neighbourhood been defined quite pessimistically. With this the 

statistics. Above a potential accumulation cell, the run-out zones are large enough and rather too 

raster cells inside a 20° sector will be analysed large in the case of doubt. 

(Fig. 6). Accumulation will be calculated if there 

is a starting zone and if the topography in the 7. Subrosion / karstification 

sector named above is not convex. Every step of 

expansion will analyse the neighbourhood up to a Superficial or near-surface subrosion features 

defined distance (4 cells; red circle in Fig. 6). With (sinkholes) and the knowledge of subrodable 

every step, the hypothetical starting volume and sediments serve as criteria for the analysis of 

the rest volume will be reduced by a degradation a process area. In the first stage, the following 

factor, which depends foremost on the slope hazard areas are distinguished: 

Fig. 6: Calculation of accumulation: for the central cell with 

exposition of 210° –230°, the 20° sector identifies 3 cells 

that are either starting zones or already show accumulation 

(orange cells). 

Abb. 6: Berechnung der Auslaufbereiche: Für die Rasterzelle 

in der Mitte mit der Zellexposition 210°–230° wurden 

drei Rasterzellen im Sektor von 20° ermittelt, die sowohl 

Anbruchzone als auch Auslaufbereich sind (orange Rasterzellen). 

Verified karstification features from the 

Geological map, event register or remote sensing 

(e.g. DEM) methods. In the first stage, superficial 

or near-surface subrosion features (e.g. sinkholes, 

depressions, clefts) are visualised. There is 

no differentiation between fossil and current 

subrosion features. The second stage includes 

the visualisation of the dispersion of karstifiable 

sediments. Hazard fields can be derived using 

a point or area statistical evaluation (e.g. using 

the feature density or a raster based density 

calculation), as well as using influencing factors, 

such as geology, tectonics and hydrogeology. 

The result of the second stage determines 

the differentiation of hazard areas. Where 

applicable, the hazard areas can be coupled 

with general geotechnical recommendations as 

to construction work in karst landscapes. Special 

conditions in individual states, e.g. mining 

The hazard map has been worked out for a regional 

scale (1:25,000). Therefore the boundaries of the 

hazard areas are not sharply bounded lines and 

a detailed view on particular areas or objects is 

not allowed. In addition, the modelling of the 

different processes can make no claim to be 

complete. The maps show potentially endangered 

areas that have been determined on the basis of 

available information and that has been computed 

with modern numerical models. Anthropogenic 

preventive measures have not been introduced 

into the models. 

Improbable and extreme events have not 

been considered. Instead, frequently occurring 

events have been modelled since they are more 

representative and felt more as a risk. From a 

geological view, rare and extreme events have 

to be accounted as an unavoidable residual and 

remaining risk. 

The hazard maps for rock fall of single 

blocks and rock fall masses and deep-seated 

landslides are based on field work for the most 

part. On the contrary, the hazard areas of shallow 

landslides are solely based on computer models 

and represent a typical susceptibility map. 

Therefore, they are presented as hatched areas. 

In the field, witnesses of former traces of shallow 

landslides are hard to find due to weathering. 

However, if the predicted consequences of


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climate change with an increase in extreme 

rainfalls will come true, an increasing number of 

shallow landslides must be taken into account. 

Climate change predictions could be 

implemented in the model if maps with predicted 

precipitation on a local scale were available. 

This would allow the identification of hot spots 

with heavy rainfall and, therefore, a higher 

susceptibility for landslides. The identification of 

such hot spots is one target in the Alpine Space 

Programme project AdaptAlp that also focuses 

on evaluation, harmonizing and improvement of 

different methods for hazard mapping. 

9. Conclusions 

A hazard map is a very helpful tool for planning 

authorities to get an overview about land use 

conflicts and potentially endangered areas. It is 

a general map created under objective scientific 

criteria and indicating geological hazards that 

have been identified and localized but not 

analysed and evaluated in detail. A hazard map 

does not contain specifications about the degree 

of hazard or the intensity or probability of an 

event. 

The map will be provided to local and 

regional planning authorities for water, traffic, 

and forest management. It helps the planner 

identify hot spots and make decisions concerning 

measures of protection. On the other hand, it also 

shows areas not endangered and free for planning. 

In critical cases, the hazard map has 

to disclose the requirement for further analysis. 

In this cases a detailed expertise analysis has 

to decide if measures are technically feasible, 

economically reasonable and under sustainable 

aspects really necessary. 

To help potential users interpret the 

hazard map, the results are presented to all 

authorities. Furthermore, an intensive cooperation 

with the Bavarian Environment Agency is offered. 

In addition, a limited version of the hazard map is 

published on the Internet (www.bis.bayern.de). 

But the Alpine part of Bavaria is not the 

only region affected by geological hazards. The 

Alpine foothills and the Swabian-Franconian 

Jurassic-mountains are affected as well. For the 

mid-term, the goal is to develop hazard maps for 

the whole of Bavaria. 


Karl Mayer 





Andreas von Poschinger 






BUNDESAMT FÜR RAUMENTWICKLUNG, BUNDESAMT FÜR 

WASSER UND GEOLOGIE, BUNDESAMT FÜR UMWELT, WALD UND 

LANDSCHAFT (BUWAL) [eds.] (2005): 

Empfehlungen Raumplanung und Naturgefahren. – 50 p., Bern. 

EVANS, S. G. & HUNGR, O. (1993): 

The assessment of rock fall hazards at the base of talus slopes. – Canadian 

Geotechnical Journal, 30 (4): 620-636, Ottawa (Nat. Res. Council of 

Canada). 

HEGG, C. & KIENHOLZ, H. (1995): 

Deterministic paths of gravity-driven slope processes: The „Vector Tree 

Model“. In: Carrara, A. & Guzzetti, F. (eds.): Geographical Information 

Systems in Assessing Natural Hazards, 79 – 92, Dordrecht. 

KIENHOLZ, H., ERISMANN, TH., FIEBIGER, G. & MANI, P. (1993): 

Naturgefahren: Prozesse, Kartographische Darstellung und Maßnahmen. 

– In: Tagungsbericht zum 48. Deutschen Geographentag in Basel, 293 – 

312, Stuttgart. 

KRUMMENACHER, B., PFEIFER, R., TOBLER, D., KEUSEN, H. R., LINIGER, 

M. & ZINGGELER, A. (2005): 

Modellierung von Stein- und Blockschlag; Berechnung der Trajektorien auf 

Profilen und im 3-D Raum unter Berücksichtigung von Waldbestand und 

Hindernissen. – anlässlich Fan-Forum ETH Zürich am 18.02.2005, 9 p., 

Zollikofen. 

LIED, K. (1977): 

Rockfall problems in Norway. – In: Istituto Sperimentale Modelli e Strutture 

(ISMES), 90: 51-53, Bergamo. 

LIENER, S., (2000): 

Zur Feststofflieferung in Wildbächen. Geographisches Institut Universität 

Bern. Geographica Bernensia G64, Bern. 

MAYER, K. & VON POSCHINGER, A. VON (2005): 

Final Report and Guidelines: Mitigation of Hydro-Geological Risk in Alpine 

Catchments, “CatchRisk”. Work Package 2: Landslide hazard assessment 

(Rockfall modelling). Program Interreg IIIb – Alpine Space. 

MAYER, K., PATULA, S., KRAPP, M., LEPPIG, B., THOM, P., POSCHINGER, 

A. VON (2010): 

Danger Map for the Bavarian Alps. Z. dt. Ges. Geowiss., 161/2, p. 119-128, 

10 figs. Stuttgart, June 2010 

MEISSL, G. (1998): 

Modellierung der Reichweite von Felsstürzen. – In: Innsbrucker 

Geographische Studien, 28: 249 p., Innsbruck (Selbstverl. des Instituts für 

Geographie der Universität Innsbruck). 

ONOFRI, R. & CANDIAN, C. (1979): 

Indagine sui limiti di massima invasione dei blocchi franati durante il sisma 

del Friuli del 1976. – Regione Autonoma Friuli-Venezia Giulia e Università 

degli Studi di Trieste, 41 p., Trieste (Cluet Publisher). 

PERSONENKREIS “GEOGEFAHREN“ (2008): 

Geogene Naturgefahren in Deutschland – Empfehlungen der Staatlichen 

Geologischen Dienste (SGD) zur Erstellung von Gefahrenhinweiskarten; 

not published. 

SELBY, M.J. (1993): 

Hillslope Materials and Processes, Oxford University Press, Oxford. 

UMWELTBUNDESAMT [eds.] (2008): 

Klimaauswirkungen und Anpassung in Deutschland – Phase 1: Erstellung 

regionaler Klimaszenarien für Deutschland. – http://www.umweltdaten.de/ 

publikationen/fpdf-l/3513.pdf 

WADGE, G., WISLOCKI, A.P. & PEARSON, E.J. (1993): 

Spatial analysis in GIS for natural hazard assessment. In: Goodchild, M.F., 

Parks B.O. & Steyaert, L.T. (Hrsg.) – Environmental modelling with GIS: 

332-338, New York, Oxford. 

WIECZOREK, F. G., MORRISSEY, M. M., IOVINE, G. & GODT, J. (1999): 

Rockfall Potential in the Yosemite Valley, California. – In: U.S. Geological 

Survey Open-File Report 99-0578, http://pubs.usgs.gov/of/1999/ofr-99- 

0578/.


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DIDIER RICHARD 


for Rapid Mass Movements in France 

Standards und Methoden der Gefährdungsanalyse 

für schnelle Massenbewegungen in Frankreich 

Summary: 

Hazard assessment is required for different purposes and is carried out through expertise 

assessments at different levels, using various approaches. Hazard assessment and mapping 

methods are standardized at least for their use in the frame of land-use planning in what is 

called the plan for the prevention of natural hazards (plan de prévention des risques naturels 

prévisibles, PPR). This is one of the main instruments used by the French national authorities 

for preventing natural hazards while taking them into account in land use development. 

Within this procedure, a general methodological guidelines document and other 

documents specific to the different types of hazards specify the conditions and clarify the 

method and approach proposed to draw up the PPR. One of these documents is dedicated 

to mass movement hazards. In this procedure, the hazard map is an intermediate step in 

elaborating the risk map, i.e. the regulations stemming from the PPR (together with the 

associated regulations). 

Various types of information available and databases can be used for hazard 

assessment and hazard mapping, based on an inventory of phenomena and a back-analysis 

of current and past events. 

Hazard assessment must characterize a given hazard in terms of intensity and 

frequency of occurrence. For mass movements, specific approaches are proposed, given the 

specific characteristics of these phenomena. 


Gefahrenbeurteilungen sind für verschiedene Zwecke erforderlich und werden in Form von 

fachlichen Gutachten auf unterschiedlichen Ebenen anhand verschiedener Ansätze vorgenommen. 

Gefährdungsbeurteilung und Kartierungsmethoden sind zumindest für die Verwen- 

dung im Rahmen der Flächennutzungsplanung standardisiert: Der Plan für die Verhinderung 

von Naturgefahren (plan de prévention des risques naturels prévisibles, PPR) ist eines der 

wichtigsten Mittel der französischen nationalen Behörden für die Vermeidung natürlicher 

Gefahren und findet in der Flächennutzungsplanung Berücksichtigung. 

Im Rahmen dieses Verfahrens beschreiben allgemeine methodologische Richtlinien 

und andere, für die verschiedenen Arten von Gefahren spezifische Dokumente die Bedingungen 

und geben Aufschluss über die empfohlenen Methoden und Ansätze zum Erstellen 

des PPR. Eines dieser Dokumente befasst sich mit den durch Massenbewegungen verursachten 

Gefahren. In diesem Verfahren ist der Gefahrenzonenplan ein Zwischenschritt in 

der Erstellung des Risikoplans, d.h., die Vorgaben stammen vom PPR (gemeinsam mit den 

zugehörigen Bestimmungen). 

Für die Erstellung von Gefährdungsanalysen und die Gefahrenzonenplanung (Gefahrenkartierung) 

stehen – beruhend auf einem Bestand von Phänomenen und einer Analyse 

aktueller und vergangener Ereignisse – verschiedene Arten von Informationen und Datenbanken 

zur Verfügung. 

Gefährdungsanalysen müssen eine gegebene Gefahr in Bezug auf die Intensität und 

Häufigkeit des Auftretens beschreiben. Für Massenbewegungen sind spezifische Ansätze 

empfohlen, welche die spezifischen Merkmale dieser Erscheinungen berücksichtigen. 

Introduction 

Hazard assessment of rapid mass movements 

is required for different purposes than for other 

natural phenomena. Depending on the objectives, 

this must be carried out at different scales. Hazard 

assessment can also take different forms, but 

most often its final outcome is a hazard map. 

Different types of expertise from various experts 

and approaches contribute to hazard assessment. 

Therefore, establishing standardized approaches, 

methods and tools is demanding. The field of landuse 

planning, however, integrates standardized 

hazard assessment and mapping methods. 

Hazards mapping and land-use planning 

Natural hazards must be taken into account in landuse 

planning documents. These are mainly schemes 

of territorial coherence at an inter-urban scale and 

local urban planning at the community scale. 

Typically, urban planning procedures 

and decisions, under the jurisdiction of national or 

local authorities, must integrate natural hazards. 

The plan for prevention of natural hazards (plan de 

prévention des risques naturels prévisibles - PPR) 

established by the law of February 2, 1995, is now 

one of the national authority’s main instruments 

for preventing natural hazards. The PPR is a 

specific procedure designed to take into account 

natural hazards in land-use development. 

The PPR is elaborated under the authority 

of the department’s prefect, which approves it 

after formal consultation with municipalities and 

a public inquiry. The PPR involves the local and 

regional authorities concerned from the very first 

steps of its preparation (Fig. 1). It can cover one 

or several types of hazards and one or several 

municipalities.


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For areas exposed to greater hazards, the PPR is 

a document which informs the public on zones 

that expose populations and property to hazards. 

It regulates land use, taking into account natural 

hazards identified in this zone and goals of 

nonaggravation of risks. This regulation extends 

from authorising construction under certain 

conditions to prohibiting construction in cases 

where the foreseeable intensity of hazard or the 

nonaggravation of existing risks warrants such 

action. This guides development choices on less 

exposed land in order to reduce harm and damage 

to persons and property. 

The PPR is designed for urban planning 

and is incumbent on everybody: individuals, 

companies, communities and government 

authorities, especially when delivering building 

permits. It must therefore be annexed to 

the local urban planning plan when such a 

document exists. 

The basis for the regulation of projects 

in the perimeter of a PPR is to discontinue 

development in areas with the greatest hazard 

and, therefore, to prohibit land development 

and construction. This principle must be strictly 

Fig. 1: PPR 

elaboration 

scheme (Source: V. 

Boudières; 2008) 

Abb. 1: Programm 

zur Ausarbeitung 

eines PPR (Quelle: 

V. Boudières; 2008) 

applied when the safety of persons is involved. 

In other cases, this principle remains particularly 

warranted by the cost of preventive measures to 

reduce the vulnerability of future constructions 

and the cost of compensation in cases of 

disaster, financed by society. However, since 

the prevention objectives are then based on 

economic considerations, it is possible to discuss 

the limits of prohibitions and requirements with 

local actors, elected officials and economic and 

consumer representatives without departing from 

this principle. Adjustments can be accepted when 

the situation does not allow alternatives. For 

example in urban centres, where requirements 

to reduce the vulnerability of projects and 

preventive, protection and safety measures 

allowing the organization of emergency services 

will be set up. 

The PPR may operate in zones that are 

directly at risk, but also in other zones that are 

not in order to avoid aggravating existing risks 

or causing new ones. It regulates projects for 

new installations. It may prohibit or impose 

requirements on any type of construction, 

structure, development or any farming, forestry, 

craft, commercial or industrial activity, for their 

completion, use or exploitation and requirements 

of any kind can be used, up to total prohibition. 

The PPR may also define general preventive, 

protection and safety measures that must be 

taken into account by communities as well as 

individuals. This option particularly concerns 

measures relating to the safety of persons and the 

organization of rescue operations as well as all 

general measures that are not specifically related 

to a particular project. 

Finally, the PPR may take an interest 

in existing structures as well as new projects. 

However, for property construction that has been 

allowed in the past, only limited improvements 

whose cost is less than 10% of the market or 

estimated value of the property can be required. 

As a complement to the PPR – the central 

tool of the French national authorities’ natural 

hazards prevention action – other procedures 

and tools are designed to provide preventive 

information that must be provided to inhabitants 

possibly exposed to hazards (information tools: 

DDRM, DCS, DICRIM, IAL, etc.) as well as 

measures relating to the safety of persons and the 

organization of rescue operations that must be 

taken into account by communities and private 

individuals (safety measures plan: PCS). These 

procedures are mandatory for the municipalities 

with an existing PPR. Danger studies are also 

mandatory for certain classes of hydraulic works 

(new regulations for dams and dikes). Adequate 

hazard assessment (and mapping) is of course also 

necessary for all these prevention tools. 

Rapid mass movements 

Approximately 7,000 French municipalities are 

threatened by mass movements, one-third of 

which can be highly dangerous for the population. 

Most of these towns, located in mountain regions, 

are exposed to various phenomena stemming 

from the instability of slopes and cliffs (collapses, 

rock falls, landslides). 

Mass movements are demonstrations 

of the gravitational movement of ground masses 

destabilized under the influence of natural 

solicitations (snow melting, abnormally heavy 

rainfall, an earthquake, etc.) or human activities 

(excavation, vibration, deforestation, exploitation 

of materials or groundwater, etc.). 

They vary greatly in form, resulting from 

the multiplicity of triggering mechanisms (erosion, 

dissolution, deformation and collapse under 

static or dynamic load), themselves related to the 

complexity of the geotechnical behaviour of the 

materials (geologic structure, geometry of the 

fracture networks, groundwater characteristics, etc.) 

According to the velocity of movement, two 

groups can be distinguished: 

• Slow movements, for which the deformation 

is progressive and can be accompanied by 

collapse but in principle without sudden 

acceleration: 

Ground subsidence consecutive 

to changes in natural or artificial 

subterranean cavities (quarries or mines); 

Compaction by shrinkage of clayey 

grounds and by consolidation of certain 

compressible grounds (muck, peat); 

Creep of plastic materials on low slopes; 

Landslides, i.e. a mass movement along 

a flat, curved or complex discontinuity 

surface of cohesive grounds (marls and 

clays); 

Shrinkage or swelling of certain clayey 

materials depending on their moisture 

content. 

• Rapid movements which can be split into 

two groups, according to the propagation 

mode of materials:


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The first group includes: 

Subsidence resulting from the sudden 

collapse of the top of natural or artificial 

subterranean cavities, without damping 

by the surface layers; 

Rock falls resulting from the mechanical 

alteration of fractured cliffs or rocky 

scarps (volumes ranging from 1 dm 3 to 

10 4 or 10 5 m 3 ); 

Some rock slides. 

The second group includes: 

Debris flows, which result from the 

transport of materials or viscous or fluid 

mixtures in the bed of mountain streams; 

Mud flows, which generally result from 

the evolution of landslide fronts. Their 

propagation mode is intermediate between 

mass movement and fluid or viscous 

transport. 

Standards and methods 

In France’s administrative and institutional 

organization, certain activities and policies remain 

the jurisdiction of centralised authorities, such as 

the policy for natural risk prevention, overseen by 

the Ministry of the Environment. This is probably 

one of the most significant differences compared 

with other Alpine countries. One consequence 

is the willingness to maintain a minimum 

homogeneity and coherence at the national level 

and in the way different types of natural hazards 

are treated. 

Within the framework of this common 

procedure, a general methodological guidelines 

document has been published, followed by others 

specific to the different types of hazards: floods, 

forest fires, earthquakes, snow avalanches (to be 

approved), torrential floods (to be approved)… 

One of these guideline documents is dedicated 

to geological hazards, including subsidence, 

sinking, collapse, rock falls, landslides, and 

associated mud flows, but it excludes debris flows 

in general. 

The general guide, published in August 

1997, presents the PPR, specifies how it should 

be drawn up and tries to answer the numerous 

questions that may arise for their implementation. 

The other guidelines, such as the one dedicated 

to mass movements, clarify the method and 

approach proposed for the various types of risks. 

The general methodology establishes that the PPR 

is composed of: 

• a presentation report explaining the 

analysis of the phenomena considered 

and the study of their impacts on people 

and existing or future property. This report 

explains the choices made for prevention, 

stating the principles the PPR is based on 

and commenting the regulations adopted. 

• a regulatory map at a scale generally 

between 1:10,000 and 1:5,000, which 

delineates areas controlled by the PPR. 

These are risk-prone areas but also areas 

where development could aggravate the 

risks or produce new sources of risk. 

• regulations applied to each of these areas. 

The regulations define the conditions 

required for carrying out projects, 

prevention, protection and safety measures 

that must be taken by individuals or 

communities, but also measures applicable 

to existing property and activities. 

The regulatory zoning of the PPR is based on 

risk assessment, which depends on the analysis 

of the natural phenomena that may occur and 

of their possible consequences in terms of land 

use and public safety. This analysis includes four 

preliminary stages: 

• Determination of the risk basin and the 

study perimeter; 

• Knowledge of the historic and active natural 

phenomena: inventory and description; 

• Hazard qualification: characterization of 

natural phenomena which can arise within 

the study perimeter; 

• Evaluation of the socioeconomic and 

human stakes subjected to these hazards. 

The elaboration of the PPR generally begins 

with the historical analysis of the main natural 

phenomena that have affected the studied 

territory. This analysis, possibly supplemented 

by expert advice on potential hazards, results 

Fig. 2: The PPR 

methodological 

guidelines collection 

Abb. 2: Die 

Sammlung methodologischer 

Richtlinien für 

einen PPR 

Fig. 3: Positioning of the 

hazard map within the 

general procedure of PPR 

elaboration 

Abb. 3: Positionierung des 

Gefahrenzonenplans in der 

allgemeinen Ausarbeitungsphase 

eines PPR


Seite 136 

Seite 137 

in a hazard map that evaluates the scope of 

predictable phenomena. This map, including an 

analysis of the territory outcomes carried out in 

consultation with the various local partners, is 

the basis for reflection during the elaboration 

of the PPR. Combining the levels of hazard and 

outcomes allows defining risk zones. 

Therefore, in this procedure the hazard 

map is an intermediate step necessary to elaborate 

the risk map, i.e. the real regulatory outcome of 

the PPR (together with the associated regulations). 

The study of phenomena by risk basin produces 

the hazard map, which is combined with the 

identification of elements at risk in drawing up the 

risk map. 

Data and information 

The first step in elaborating hazard maps consists 

of collecting all available data and information 

that can be exploited for hazard assessment. 

Priority is given to the qualitative general studies 

and to the back-analysis of past events. The 

general studies are conducted based on existing 

data, the back-analysis of past or current events 

and field surveys. Priority must be given to these 

elements, as stipulated by article 3 of the decree 

of October 5th, 1995, which specifies that the 

elaboration of PPR takes into account the current 

state of knowledge. 

The main information sources are: 

• Municipal archives (technical documents, 

deliberations, miscellaneous documents, 

petitions, general reports or accident 

reports, etc.); 

• Parochial archives; 

• Departmental sources (archive and quarry 

services, miscellaneous diagnoses, etc.); 

• Engineering consulting firm documents 

(geotechnical and geological reports, civil 

engineering studies and reports, field visit 

reports, etc.); 

• General and research documents (scientific 

papers, geological guides, monographs, 

PhD theses, etc.); 

• Field surveys and eye witness accounts; 

• Existing databases and maps, aerial 

photographs. 

Historical and existing studies as well as field 

investigations are collected for the study of the 

Fig. 5: 

Geological 

maps and 

databases 

(www. 

brgm.fr) 

Abb. 5: 

Geologische 

Karten und 

Datenbanken 

(www. 

brgm.fr) 

Study of phenomena 

by risk basin 

Identification of 

elements at risk 

Regulatory 

documents 

Historical and existing 

studies, field investigation 

Informative map of 

natural phenomena 

Hazard map 

Necessary information and consultation 

Available maps and data bases 

Elements at risk 

appreciation 

Risk Prevention 

Plan (PPR) 

Risk management 

Annexation as 

servitude in the PLU 

Fig. 4: 

The first 

step of 

hazard 

mapping 

Abb. 4: 

Der erste 

Schritt 

der 

Gefahrenzonenplanung 

Fig. 6: 

Example of 

a ZERMOS 

map 

Abb. 6: 

Beispiel 

eines 

ZERMOS- 

Plans


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Intensity level 

Low 

Coutermeasures importance level 

Can be financed by an individual owner 

phenomena step. Maps and databases are available 

for this work: geological maps at a 1:50,000 scale, 

covering France (Fig. 5 - www.brgm.fr); a few 

Zermos maps (Fig. 6) of zones exposed to soil 

movement hazards, a combination of susceptibility 

levels and geomorphologic features, which are 

quite old and not exhaustive; a French database 

of mass movements (Fig. 7 - www.bdmvt.net); 

and an events database of the RTM services that 

will soon be on line. 

Hazard assessment 

Hazard evaluation includes three components: 

the intensity of mass movements, the time of 

occurrence and the spatial extension. Once 

translated into regulatory zoning, the information 

contained in this map will be used to manage and 

plan land development and construction works. 

Hazards are thus qualified in terms of intensity. 

Considering the variety of mass movements, 

Fig. 7: The 

BDMVT, 

French 

database 

of mass 

movements 

(www. 

bdmvt.net) 

Abb. 7: 

BDMVT 

– französische 

Datenbank 

für 

Massenbewegungen 

(www. 

bdmvt.net) 

it is difficult to directly translate their physical 

characteristics in terms of intensity, except by 

defining as many hazards as movement types, 

which would make the hazard zoning document 

difficult to read. It is therefore necessary to refer to 

more global criteria so they can be compared and 

their use for regulatory zoning facilitated. 

Different methods are possible to assess a 

representative intensity level for all phenomena: 

• As for earthquakes, intensity can be 

translated in terms of potential for damage, 

using parameters such as the volume of 

soil or rock involved, the depth of the 

failure surface, the final displacement, 

the kinetic energy, etc. However, damage 

potential depends not only on the physical 

phenomenon, but also on the vulnerability 

of buildings, which introduces a bias. 

• Intensity can be assessed according to 

the importance and the cost of protection 

measures that would be necessary to 

Medium 

High 

Major 

Can be financed by a limited group of owners 

Fig. 8: Example of relationships proposed between the importance of countermeasures and intensity level 

Abb. 8: Beispiel der empfohlenen Beziehungen zwischen der Bedeutung der Gegenmaßnahmen und der Intensitätsstufe 

implement. Different classes of intensity can 

be identified if these measures remain within 

the domain of an individual owner or a group 

of owners or if they require community 

intervention and investment (Fig. 8). 

Geological hazard qualification is based on 

qualitative criteria, such as the observed or expected 

damage or impacts or the cost range of possible 

countermeasures for the intensity evaluation. 

The frequency of events is estimated on 

the basis of the historical events identified on 

the site. The reference hazard is the most severe 

potential events considered by the expert as likely 

to occur in a 100-year period (or more frequently 

if human lives are concerned), or the most severe 

historical event identified on an equivalent site. 

The probabilistic approach based on 

a frequency analysis is possible only for some 

phenomena such as rock falls. This assumes that 

sufficient data are available, which is actually 

rare. As most mass movements are not repetitive 

processes, contrary to earthquakes or floods, it is 

necessary to consider a probability of occurrence 

of an event qualitatively over a given period (e.g. 

50 or 100 years), without reference to numerical 

values. For instance, three levels or probabilities 

may be used: low, medium and high. 

Concerns a spatial area larger than the individual 

ownership scale and/or very higth cost and/or technically 

difficult 

No possible technical countermeasure 

Only a few cases in France (Séchilienne, la Clapière...) 

In most cases, the occurrence probability is not 

a true probability, but is simply a scale of relative 

susceptibility, relying on elements such as slope 

angle, lithology, fracturing of the rock mass, 

presence of water, etc. 

The hazard is graded by combining the 

time occurrence and the intensity, typically in a 

2D table (Fig. 10). There is no general specification 

for this stage of the hazard evaluation, but 

presenting the key of the hazard evaluation is 

strongly recommended. 

In the presence of substantial human 

and socioeconomic danger, methods and 

tools specifying the spatial extension of the 

phenomena, thus reducing uncertainty, can be 

used: run-out modelling for rock falls, geophysics 

surveys delineating underground mines, etc. In 

case of rock falls and related phenomena, hazard 

evaluation includes both the stability analysis 

of rock masses and run-out distance evaluation. 

Numerical tools are increasingly used to estimate 

the maximal run-out distance, but the reliability of 

the results is highly dependent on the experience 

of the engineering geologist. 

Generally, the topographic basis used is 

the IGN (National Geographic Institute) 1:25,000 

map, enlarged to 1:10,000. In presence of


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Seite 141 

Conclusion 

Acknowledgements 

Fig. 9: Decision process for assessing the reference hazard 

Abb. 9: Entscheidungsprozess zur Bewertung der Bezugsgefährdung 

substantial damage potential or if the precision 

of the study and the amount of available data 

allow it, it is possible to map the hazards on a 

or Séchilienne (Isère), involving more than 10 

million cubic metres of material, ad hoc methods 

of hazard assessment have been set up, including 

1:5,000-scale map. 

the monitoring of movement and various 

As far as very large mass movements are computer simulations. 

concerned, such as La Clapière (Alpes-Maritimes) 

Probability of occurrence 

Methods assessing hazards for rapid mass 

movements are still mostly empirical and rely 

on the experience of the engineering geologist. 

The PPR guidelines give a general framework 

and general principles for hazard assessment and 

mapping. Precise rules are not yet available at the 

national level. The geological analysis remains the 

basis of hazard evaluation, but numerical tools as 

GIS and computer simulation are also used. The 

main requirement is that the method used should 

be explained. 


Didier Richard 

Cemagref – Unité de Recherche 

“érosion torrentielle, neige et avalanches” 

BP 76 – F 38402 Saint-Martin-d’Hères Cedex 

Tel. : +33 4 76 76 27 73 

mail : didier.richard@cemagref.fr 

Jean-Louis Durville, Conseil général de 

l'environnement et du développement durable. 

Alison Evans, Service de Restauration des Terrains 

en Montagne de Haute-Savoie. 

The person to contact for more information on this 

policy within the French Ministry of Sustainabledevelopment, 

is François Hédou (Francois. 

HEDOU@developpement-durable.gouv.fr). 


RISK PREVENTION FRENCH WEBPORTAL: www.prim.net 

RISK MAPPING: 

http://cartorisque.prim.net/ 

WEBSITE OF THE FRENCH MINISTRY IN CHARGE OF RISK PREVENTION 

POLICY: http://www.developpement-durable.gouv.fr/ 

FRENCH MASS MOVEMENTS DATABASE: http://www.bdmvt.net/ 

BRGM (bureau de recherches géologiques et minières) Website: http:// 

www.brgm.fr/ 

LCPC (1999) 

L'utilisation de la photo-interprétation dans l'établissement des plans 

de prévention des risques liés aux mouvements de terrain. Collection 

Environnement, 128 p. 

LCPC (2000) 

Caractérisation et cartographie de l'aléa dû aux mouvements de terrain. 

Collection Environnement, 91 p. 

MINISTÈRE DE L'AMÉNAGEMENT DU TERRITOIRE (1999). 

Plans de prévention des risques naturels (PPR). Risques de mouvements de 

terrain. La Documentation française, 71 p. 

Intensity level 

Low 

Determining factors 

identified on the site are 

diffuse, poorly determined. 

Medium 

Many determining factors are 

identified on the site. Some 

factors unlisted can appear 

with time. 

High 

Some nonidentified determining 

factors on the 

site. The intensity of the 

factors is high. 

Low 

Rock Falls < 1 dm 3 

Very low to low 


Very low to low hazard / 

Medium 

Rock Falls < 100 m 3 

Very low to low 


Medium hazard 

High hazard 

High 

Collapses > 100 m 3 / High hazard High hazard 

Abb. 10: Beispiel für die Erstellung einer Übersichtstabelle über Steinschlaggefahr (von CETE du sud-ouest) 

Fig 10: Example of hazard table determination for rock fall hazard (from CETE du sud-ouest)


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PERE OLLER, MARTA GONZÁLEZ, JORDI PINYOL, JORDI MARTURIÀ, PERE MARTÍNEZ 

Geohazards Mapping in Catalonia 

Kartierung von geologischen Gefahren in Katalonien 

Summary: 

This paper presents the different lines of work being undertaken by the Geological Institute 

of Catalonia (IGC) on geological hazard mapping. It describes the different map series, scales 

of representation, methodologies and its expected use. 

Keywords: hazard mapping, geohazards, Catalonia. 


Diese Abhandlung bietet einen Überblick über die verschiedenen Aktivitäten des Geologischen 

Instituts Katalonien (IGC) für die Kartierung geologischer Gefahren. Sie beschreibt die 

unterschiedlichen Kartenserien, den Umfang der Darstellungen, die angewandte Methodik 

und den erwarteten Gebrauch der Karten. 

Schlüsselwörter: Gefahrenkartierung, Geogefahren, Katalonien. 

Introduction 

With Law 19/2005, the Parliament of Catalonia 

approved the creation of the Geological Institute 

of Catalonia (IGC) assigned to the Ministry of 

Land Planning and Public Infrastructures (DPTOP) 

of the Catalonian Government. 

One of the functions of the IGC is to 

“study and assess geological hazards, including 

avalanches, to propose measures to develop 

hazard forecast, prevention and mitigation and 

to give support to other agencies competent in 

land and urban planning, and in emergency 

management”. Therefore, the IGC is in charge of 

making official hazard maps for such a finality. 

These maps comply with the Catalan Urban Law 

(1/2005) which indicates that building is not 

allowed in those places where a risk exists. 

The high density of urban development 

and infrastructures in Catalonia requires 

geo-thematic information for planning. As 

a component of the Geoworks of the IGC, 

the strategic programme aimed at acquiring, 

elaborating, integrating and disseminating the 

basic geological, pedological and geothematic 

information concerning the whole of the territory 

in scales suitable for land and urban planning. 

Geo-hazard mapping is an essential part of this 

information. Despite some tests carried out with 

wide land recovery (Mountain Regions Hazard 

Map 1:50,000 [DGPAT, 1985], Risk Prevention 

Map of Catalonia 1:50,000 [ICC, 2003]), at 

present the work is done mainly on two scales: 

land planning scale (1:25,000), and urban 

planning scale (1:5,000 or more detailed). These 

scales imply different approaches and methods to 

obtain hazard parameters used for such a purpose. 

The maps are generated in the framework of a 

mapping plan or as the final product of a specific 

hazard report. These different types of hazard 

mapping products are explained below. 

Geological Hazard Prevention Map of Catalonia 

1:25,000 (MPRGC25M) 

The most important mapping plan is the Geological 

Hazard Prevention Map of Catalonia 1:25,000 

(MPRGC25M). This project started in 2007. The 

MPRGC includes the representation of evidence, 

phenomena, susceptibility and natural hazards 

of geological processes. These are the processes 

generated by external geodynamics (such as slope, 

torrent, snow, coastal and flood dynamics) and 

internal (seismic) geodynamics. The information 

is displayed by different maps on each published 

sheet. The main map is presented on a scale of 

1:25,000, and includes landslide, avalanche and 

flood hazard. The hazard level is qualitatively 

classified as high (red), medium (orange) and low 

(yellow). The methods used to analyze hazards 

basically consist of geomorphological, spatial and 

statistical analysis. 

Several complementary maps on a 

1:100,000 scale show hazards caused individually 

by different phenomena in order to facilitate the 

Fig. 1: First published sheet, Vilamitjana (65-23), in 2010. 

Abb. 1: Das erste veröffentlichte Blatt, 

Vilamitjana (65-23), 2010.


Seite 144 

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reading of the sheet and understanding of the 

mapped phenomena. Two additional maps for 

flooding and seismic hazards, represented on 

a 1:50,000 scale, are added to the sheet. The 

map is to provides government and individuals 

with an overview of the territory with respect to 

geological hazards, identifying areas where it is 

advisable to carry out detailed studies in case of 

action planning. At the same time, a database 

is being implemented. It will incorporate all the 

information obtained from these maps. In the 

future it will become the Geological Hazard 

Information System of Catalonia (SIRGC). 

The procedure followed in the main map consists 

of three steps: 

1.Catalogue of phenomena and evidences 

2.Susceptibility determination 

3.Hazard determination 

The catalogue of phenomena and evidence is 

the base of the further susceptibility and hazard 

analysis. It consists of a geomorphologic approach 

and it comprises the following phases: 

1. Bibliographic and cartographic search: the 

information available in archives and databases 

is collected. 

2. Photointerpretation: carried out on vertical 

aerial photos of flights from different years 

(1957, 1977, 1985, 2003, etc.). The observation 

of the topography and the vegetation allows 

the identification of areas with signs of 

instability coming from the identification and 

characterization of events that occurred recently 

or in the past, and from activity indicators. 

3. Field survey: checking and contrasting on the 

field, the elements identified in the previous 

phases. Field analysis allows a better approach 

and understanding, and therefore identifying 

signs and phenomena are not observable 

through the photointerpretation. 

4. Population inquiries: the goal of this stage is to 

complement the information obtained in the 

earlier stages, especially in aspects such as the 

intensity and frequency. It is done through a 

survey to witnesses who live and/or work in the 

study areas. 

In a second step, areas susceptible to be 

affected by the phenomena are identified from the 

starting zone to the maximum extent determinable 

at the scale of work. Their limits are drawn taking 

into account the catalogue of phenomena, 

geomorphological indicators of activity, and from 

the identification of favourable lithologies and 

morphologies of the terrain. This phase includes 

the completion of GIS and statistical analysis 

to support the determination of the starting and 

run-out zone. It can be extensively applied with 

satisfactory results with regard to the scale and 

purpose of the work. 

Finally, hazard is estimated on the basis 

of the analysis of the magnitude and frequency (or 

activity) of the observed or potential phenomena. 

Susceptibility areas are classified according to 

the hazard matrix represented in Fig. 2. Hazard 

zones are represented as follows: areas where 

no hazard was detected (white), zones with low 

hazard (yellow), medium hazard zones (orange), 

and areas with high hazard (red). 

In order to obtain an equivalent hazard 

for each phenomena, an effort was made to 

Fig. 2: Hazard matrix (based on Altimir et al, 2001). 

Abb. 2: Gefahrenmatrix (auf der Grundlage von Altimir et al, 2001). 

equate the parameters that define them. The 

same frequency/activity values were used for all 

phenomena, but magnitude values were adapted 

to each of them. 

Each hazard level contains some 

considerations for prevention (Fig. 3). These 

considerations inform about the need for further 

detailed studies and advise about the use of 

corrective measures. 

Fig. 3: Prevention recommendations. 

Abb. 3: Empfohlene Präventivmaßnahmen. 

Hazard from each phenomena is 

analyzed individually. The main challenge of the 

map is to easily present the overlapping hazard of 

different phenomena. A methodology identifying 

that this overlap exists has been established 

with this objective in mind. It indicates what the 

maximum overlapped hazard is (Fig. 4), but in any 

case, without obtaining new hazard values. 

Fig. 4: Multi-hazard representation. 

Abb. 4: Darstellung von Mehrfachrisiken. 

An epigraph is assigned, to identify the hazard 

level and the phenomena that causes it, especially 

in overlapping areas (Fig. 5). This epigraph 

consists of two characters, the first in capital 

letters, indicates the value of hazard (A for high 

hazard, M for medium hazard and B for low 

hazard), and the second, in lower-case, indicates 

the type of phenomena (e for large landslides, s 

for landslides, d for rockfalls, x for flows, a for 

avalanches and f for subsidence and collapses). 

The higher the overlapping is, the longer the 

epigraph will be. 

Fig. 5: Example of multi-hazard representation. 

Abb. 5: Beispiel von Mehrfachrisiken. 

Fig. 6: Main map 1:25000, which includes landslides, avalanches, 

sinking and flooding according to geomorphologic 

criteria. 

Abb. 6: Hauptkarte 1:25000; sie veranschaulicht die Gefahren 

hinsichtlich Bergstürze, Lawinen, Absenkung und Hochwasser 

nach geomorphologischen Kriterien.


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Complementary maps 

Complementary maps represent the hazard 

established for each individual phenomena at 

1:100,000 scale. The purpose of these maps is 

to facilitate the interpretation of the main map. 

Depending on the type of phenomena identified 

in the main map, the number of complementary 

maps can vary from 1 to 6. 

The final map (Fig. 8) also represents the values of 

the basic seismic acceleration of the compulsory 

"Norma de Construcción Sismorresistente 

Española" (NCSE-02) for a placement in rock, 

and the intensity of the seismic emergency plan 

(SISMICAT). 

Fig. 10: Flooding hazard map 1:100,000 based on hydraulic 

modeling. 

Abb. 10: Hochwasser-Gefahrenzonenkarte 1:100.000 auf der 

Grundlage hydraulischer Modellierung. 

Fig. 12: First published Avalanche Paths Map, “Val d’Aran 

Nord”, in 1996. 

Abb. 12: Erste veröffentlichte Lawinenzugkarte „Val d’Aran 

Nord“, 1996. 

The termination of the MZA allows a first global 

Fig. 7: Complementary map of surface landslide hazard. 

Abb. 7: Komplementärkarte über Erdrutschrisiken. 

Seismic hazard map 

This map was obtained from the map of seismic 

areas for a return period of 500 years, for a 

middle ground, and considering the effects of soil 

amplification. 

To take into account the amplification 

of the seismic motion due to soft ground, a 

geotechnical classification of lithologies from 

the Geological Map of Catalonia 1:25,000 into 

4 types was carried out: R (hard rock), A (compact 

rocks), B (semi-compacted material) and C (non 

cohesive material). This classification is based on 

the speed of the S-wave through them (Fleta et al., 

1998). The proposed amplifications were assigned 

to each group of lithologies. For types R and A no 

additions of any degree of intensity were made, 

but for types B and C, there was an addition of 

0.5 degrees of intensity. 

Fig. 8: Seismic hazard map 1:100,000. 

Abb. 8: Seismische Gefahrenzonenkarte, 1:100.000. 

Fig. 9: Seismic hazard map symbology. 

Abb. 9: Symbologie seismische Gefahrenzonenkarte. 

Flooding hazard map 

The flooding hazard map at 1:50,000 scale shows 

the limits of the hydraulic modeling for periods of 

50, 100 and 500 years provided by the Catalan 

Water Agency (ACA). A flooding map according to 

geomorphologic criteria was done in those streams 

were hydraulic modeling was not performed. 

Fig. 11: Flooding hazard map symbology. 

Abb. 11: Symbologie Hochwasser-Gefahrenzonenkarte. 

Avalanche Paths Map (MZA) 

A second mapping plan, already finished, is 

the Avalanche Paths Map (MZA). It was begun 

in 1996 and finished in 2006. An extent of 

5,092 km 2 was surveyed. During this process 

17,518 avalanche paths were mapped. This is 

a susceptibility map on a scale of 1:25,000, 

useful for land planning in the Pyrenean areas. 

The methodology is based on the French “Carte 

de Localisation des Phénomènes d’Avalanches” 

(Pietri, 1993). On this map, the avalanche paths, 

mapped from terrain analysis (photointerpretation 

and field work), are represented in orange, and the 

inventory information (witness surveys, historical 

documents, field surveys and dendrochronology) 

is represented in violet. 

vision of the avalanche hazard distribution in this 

region. The area potentially affected by avalanches 

covers 1,257 km 2 . That is at 3.91% of the Catalan 

country, and considering the Pyrenean territory, it 

affects 36%. 

At present, all the avalanche information 

is stored in the avalanche database of Catalonia 

(BDAC). New events, coming from avalanche 

observation, are added to this database. The 

information is available via the Internet at: 

http://www.icc.cat/msbdac/. 

Hazard maps for urban planning 

At present, for all the municipalities that want to 

increase their building limits, the procedure is 

first of all to make a preliminary hazard map on a 

1:5,000 scale. This element is, in fact, just a map 

of “yes or no”, which states if a hazard exists or 

not. If the municipality decides not to develop in 

hazardous areas, the process finishes. In the case 

that the municipality wants to build in the hazardzone 

areas, more detailed studies have to be 

completed. These studies include complex data 

collection, usually via drilling specific boreholes, 

other geotechnical work, and advanced modelling.


Seite 148 

Seite 149 


Pere Oller, Marta González, Jordi Pinyol, 

Jordi Marturià, Pere Martínez 

Institut Geològic de Catalunya 

C/ Balmes 209/211 

08006 Barcelona 

Fig. 13: Interface of the avalanche data server 

Abb. 13: Benutzeroberfläche des Lawinendatenservers 

The phenomena taken into account are landslides, 

rock falls, sinking and snow avalanches. In these 

maps, the hazard mapping is obtained from 

frequency/intensity analysis. Advanced modelling 

analysis is performed in order to obtain the most 

accurate results, and to support the observational 

data and expert criteria. Up to the present day, 

there is no standard methodology. The current 

challenge for the IGC is to prepare guidelines for 

such a goal in order to guarantee the standards of 

quality and homogeneity. 

There are preliminary studies of a hazard 

mapping plan 1:5,000 for snow avalanches. In 

this map terrain is classified into high hazard (red), 

medium hazard (blue) and low hazard (yellow). 

Urban planning implications regarding hazard 

have not been defined yet. An analysis of the MZA, 

supported by the statistical α−β model, resulted in 

the identification of 24 urban areas to be mapped. 

The mapping methodology includes terrain 

analysis, avalanche inventory, nivometeorological 

analysis and numerical modelling to complete the 

information. 


PIETRI, C., 1993: 

Rénovation de la carte de localisation probable des avalanches. Revue de 

Géographie Alpine nº1. P. 85-97. 

AGÈNCIA CATALANA DE L’AIGUA (Departament de Medi Ambient i 

Habitatge). Directrius de planificació i gestió de l’espai fluvial. Guia 

tècnica. 45 pp. 

ALTIMIR, J.; COPONS, R.; AMIGÓ, J.; COROMINAS, J.; TORREBADELLA, 

J. AND VILAPLANA, J.M. (2001): 

Zonificació del territori segons el grau de perillositat d’esllavissades al 

Principat d’Andorra. Actes de les 1es Jornades del CRECIT. 13 I 14 de 

setembre de 2001. P. 119-132. 

FLETA, J., ESTRUCH, I. I GOULA, X. (1998). 

Geotechnical characterization for the regional assesment of seismic risk in 

Catalonia. Proceedings 4th Meeting of the Environmental and Engineering 

Geophysical Society, pàg. 699-702. Barcelona, setembre 1998. 

NCSE-02 (2002). 

Norma de Construcción Sismorresistente Española. Parte General y de 

Edificación, Comisión Permanente de Normas Sismorresistentes, Real 

Decreto 997/2002 del 27 de septiembre de 2002, Boletín Oficial del 

Estado nº 244, viernes 11 de octubre de 2002. Ministerio de Fomento. P. 

35898-35987.


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CLAIRE FOSTER, MATTHEW HARRISON, HELEN J. REEVES 


Mass Movements in Great Britain 

Standards und Methoden der Gefahrenbewertung 

von Massenbewegungen in Großbritannien 

Summary: 

With less extreme topography and limited tectonic activity, Great Britain experiences a 

different landslide regime than countries in many other parts of the world e.g. Italy and 

France. Glacial modification of the landscape during the Pleistocene, followed by severe 

periglacial conditions have led to the presence of high numbers of ancient or relict landslides. 

Debris flows and rock falls common to higher relief areas of Europe occur but are less likely 

to interfere with development and population centres. Despite the often subdued nature of 

landslides in Great Britain, numerous high profile events in recent years have highlighted the 

continued need to produce useable, applied landslide information. The British Geological 

Survey has developed a national landslide susceptibility map which can be used to highlight 

potential areas of instability. It has been possible to create the national susceptibility map 

(GeoSure) because of the existence of vast data archives collected by the survey such as the 

National Landslide Database, National Geotechnical Database and digital geological maps. 

This susceptibility map has been extensively used by the insurance industry and has also 

been adopted for a number of externally funded projects targeting specific problems. 

Keywords 

British Geological Survey, Landslides, GeoSure, National Landslide Database 


Aufgrund einer weniger extremen Topographie und der beschränkten tektonischen Aktivität des 

Landes unterscheiden sich Auftreten und Verlauf von Erdrutschen in Großbritannien von denen 

in vielen anderen Ländern der Welt, z.B. Italien und Frankreich. Glaziale Veränderungen 

der Landschaft während des Pleistozäns, denen schwierige periglaziale Bedingungen folgten, 

haben eine hohe Anzahl von vorzeitlichen oder relikten Bergstürzen verursacht. Die für 

höhere Entlastungszonen in Europa typischen Muren und Felsstürze treten zwar auf, doch ihre 

Wahrscheinlichkeit, Entwicklungs- und Bevölkerungszentren zu beschädigen, ist gering. Trotz 

des häufig geringen Ausmaßes von Erdrutschen in Großbritannien heben zahlreiche bekannte 

Ereignisse der letzten Jahre nach wie vor die Notwendigkeit hervor, anwendbare Informationen 

über Rutschungen zu erstellen. Vom British Geological Survey (BGS) wurde eine nationale Gefahrenhinweiskarte 

für Rutschungen entwickelt, anhand derer potentielle Bereiche von Instabilität 

aufgezeigt werden können. Die Erstellung der nationalen Gefahrenhinweiskarte (GeoSure) 

war auf der Grundlage umfangreicher Datenarchive möglich, die vom BGS zum Beispiel auf 

der Grundlage der National Landslide Database, der National Geotechnical Database und von 

digitalen geologischen Karten angelegt wurden. Diese Gefahrenhinweiskarte findet beispielsweise 

in der Versicherungsbranche Anwendung und wurde für eine Reihe extern finanzierter 

Projekte übernommen, die auf bestimmte Probleme abzielen. 

Schlüsselwörter 

British Geological Survey, Rutschungen, GeoSure, National Landslide Database 

Background on landslide research and planning in 

Great Britain 

Prior to the 1966 Aberfan disaster, which 

led to the deaths of 144 people, landsliding 

was not widely considered to be particularly 

extensive or problematic in Great Britain (GB). 

In the years following the disaster, a limited 

amount of research into landslide distribution 

and mechanisms was undertaken but failed to 

lead to a structured regulatory framework for 

managing landslide risk. The Aberfan landslide 

and costly disruptions to infrastructure projects 

in the 1960/70’s (Skempton & Weeks 1976 and 

Early & Skempton 1972) strengthened the view 

that the extent of ground instability was neither 

well understood nor managed by developers or 

planners. This view led to national assessments 

of landslides being carried out in the 1980’s and 

1990’s on which the current national policy is 

largely based. These assessments provided the 

basis for planning policies and guidance that, to 

some degree, continue to control development 

on or around unstable ground. However, limited 

resources since this initial push to understand the 

problem meant that these initiatives have failed 

to develop into an effective, integrated, national 

response to deal with landslides in GB. The 

current systems, which are neither centralized nor 

legally binding, comprise a system of planning 

regulations (Town and Country Panning Act 

1990), guidance notes, operational regulations 

and building codes (Building Regulations, 2006). 

With the exception of the Building Regulations, 

none of these legal statutes specifically mention


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Seite 153 

landslides. The majority of the legislation can 

be interpreted as placing responsibility with the 

developer, utility operator or landowner to ensure 

landslides are not an issue. 

The main source of regulatory 

information regarding slope instability issues 

is contained within Planning Policy Guidance 

Note 14 (PPG14) and its associated Annex (Anon 

1990, 1994). The Annex sets out the procedure for 

landslide recognition and hazard assessment and 

emphasises the need to consider ground instability 

throughout the whole development process from 

land-use planning, through design to construction. 

These documents provide recommendations 

that slope instability be considered in any 

planning decision. If landsliding is a known 

issue, ‘a developer’ must provide evidence that 

any development activity will not exacerbate 

landslide activity and that any building will be 

safe. However, PPG14 is not legally compulsory 

and only recommends that the local planning 

authorities should endeavour to make use of 

any relevant expertise when assessing whether a 

planning application may be affected by ground 

instability. The guidance notes do not specifically 

refer to geological or geotechnical expertise 

but details of some information sources of are 

provided, including BGS data. Despite this, there 

is no legal compulsion for a planning authority 

to understand the extent or nature of landslide 

hazards within their area of concern and, thus, 

include them in planning decisions. Building 

regulations put further emphasis on the role of 

the developer to control the impact of instability 

requiring that “The building shall be constructed 

so that ground movement caused by…. land-slip 

or subsidence (other than subsidence arising from 

shrinkage), in so far as the risk can be reasonably 

foreseen, will not impair the stability of any part of 

the building.” (Anon. 2004). 

The current PPG14 predates the era of 

GIS and advises that citizens consult geological 

maps and the now defunct Department of the 

Environment Landslide Database. These sources 

of information have been superseded by the BGS’s 

‘GeoSure’ and continually updated National 

Landslide Database. Despite the availability of 

these resources, national guidance has never 

been updated to take this into account. Despite 

the advances in landslide mapping and hazard 

mapping, there is still no legal compulsion to use 

or consider it within a planning application in GB. 

Development of landslide susceptibility maps and 

databases in GB 

BGS began to map geological hazards digitally in 

the mid 1990’s. These early steps have paved the 

way for the development of much more detailed 

hazard maps that cover the whole of Great Britain 

and are complimented by detailed landslide 

mapping and an extensive National Landslide 

Database (NLD). 

The first systematic assessment of 

hazards was triggered by the insurance industry 

after it identified a need to better understand 

geological hazards. Insurance losses caused 

by ground movements (including subsidence) 

between 1989 and 1991 reached around £1- 

2bn following a particularly dry period and, as 

a result, a digital geohazard information system 

(GHASP – GeoHAzard Susceptibility Package) 

was developed by the BGS. This first decision 

support system (DSS) gave a weighted averaged 

result for each of the 10000 postcode sectors 

in GB and came to be used by around 35% of 

the Industry (Culshaw & Kelk, 1994). Since 

the development of GHASP, improvements in 

GIS technology and the availability of digital 

topographical and geological mapping for 98% 

of GB have led to advances in the methods used 

to map geohazard potential. 

The BGS has since developed a Geographical 

Information System (GIS)-based system (GeoSure) 

to assess the principal geological hazards across the 

country (Foster et al. 2008, Walsby 2007, 2008). 

One output is a GIS layer that provides ratings of 

the susceptibility of the country to landsliding on 

a rating scale of A (low or nil) to E (significant), 

which has been simplified for Fig. 1. Importantly, a 

high susceptibility score does not necessarily mean 

that a landslide has happened in the past or will 

do so in the future, but where a landslide hazard 

is most likely to occur if the slope conditions are 

adversely altered by a change in one or more of 

the factors controlling slope instability (Fig. 1). 

GeoSure is produced at 1:50,000 scale and can 

be integrated to show the spatial distribution of 

landslide susceptibility in relation to buildings and 

infrastructure. According to the dataset, 350,000 

households in the UK, representing 1% of all 

housing stock, are in areas considered to have a 

'significant' landslide susceptibility (Rated E). 

GeoSure works by modelling the causative 

factors of landsliding: lithology, slope angle and 

discontinuities being of prime importance. This has 

been made possible through the use of GIS due 

to its ability to spatially display and manipulate 

data (Soeters & Van Westen, 1996). The GeoSure 

methodology uses a heuristic approach to assess and 

classify the propensity of a geological formation to 

fail as well as to score the relevant causative factors. 

The BGS holds large amounts of information about 

the lithological nature of the rocks and soils within 

Great Britain. The National Geotechnical Physical 

Properties database contains information on the 

geographical distribution of physical properties 

(such as strength) of a wide range of rocks and soils 

present in GB. This information is vitally important 

in determining the propensity of a material to 

fail. The scores assigned to each lithology are 

based on material strength, permeability and 

known susceptibility to instability. Discontinuities 

were assessed as an important causative factor 

as they reflect the mass strength of a material, its 

susceptibility to failure and its ability to allow water 

to penetrate a rock mass. Scores were defined in 

line with those used in the British Standard 5930: 

Field Description of Rocks and Soils (British 

Standards Institute 1990) and by Bieniawski (1989). 

Analysis of known landslides showed that slope 

angle is one of the major controlling factors and 

this was derived from the NEXTMap digital terrain 

model of Britain at a 5m resolution. The scores 

for all the causative factors at each grid cell are 

combined in an algorithm to give an overall score 

based on the relative susceptibility to landsliding. 

The method is flexible enough to allow alteration 

(nationally or locally) of the algorithm in the future 

and include other factors such as the presence and 

nature of superficial deposits. 

Fig. 1: GeoSure layer showing the potential for landslide 


Abb. 1: GeoSure-Schicht veranschaulicht das Potential von 

Rutschungsgefährdungen.


Seite 154 

Seite 155 

Another important tool to both inform and assess 

landslide susceptibility in GB is the National 

Landslide Database (NLD). Landslide databases 

are commonplace in Europe but there is variability 

in their complexity and amount of further work 

carried out to further enhance or update the 

datasets. Assessing an area’s susceptibility to 

landsliding requires knowledge of the distribution 

of existing failures and also an understanding of 

the causative factors and their spatial distribution. 

This type of information is only available from a 

detailed database of past events from which one 

can draw out relevant information which may 

inform the user of where landslides may occur 

in the future. The National Landslide Database 

is the most comprehensive source of information 

on recorded landslides in GB and currently holds 

records of over 15,000 landslide events (Fig. 

2). Each of the 15,000+ landslide records can 

hold information on over 35 attributes including 

location, dimensions, landslide type, trigger 

mechanism, damage caused, slope angle, slope 

aspect, material, movement date, vegetation, 

hydrogeology, age, development and a full 

bibliographic reference. A fully digital workflow 

has been developed at BGS to enable capture 

of landslide information. The first stage of the 

process involves using digital aerial photograph 

interpretation software (SocetSet) to capture 

digital landslide polygons which can then be 

altered through field checking using BGS·SIGMA 

mobile technology (Jordan 2009; Jordan et al. 

2005). BGS·SIGMAmobile is the BGS digital field 

data capture system running on rugged tablet PCs 

with integrated GPS units, and is used extensively 

for all geological mapping activities within the 

British Geological Survey (Jordan et al., 2008). 

When collecting landslide information, 

either for the NLD or for digital maps, 

internationally recognised standards have been 

followed where appropriate. The database 

Fig. 2: Distribution of landslide database points from the 

National Landslide GIS database. OS topography © Crown 

Copyright. All rights reserved. 

Abb. 2: Verteilung der Rutschungs-Datenbankpunkte von der 

National Landslide GIS Datenbank. OS Topographie © Crown 

Copyright. Alle Rechte vorbehalten. 

dictionaries have been produced using 

internationally recognised terminology. For 

landslide type, the dictionary definitions follow 

the conventions set out by Varnes (1978), the 

EPOCH project (Flageollet, J.C., 1993) and the 

WP/WLI (1990). Age and activity of a landslide 

are important factors to record within a landslide 

inventory. Temporal landslide data is as important 

to understanding the geomorphic evolution of an 

area as the spatial distribution of slides. However, 

it is extremely difficult to date ancient landslide 

events with any degree of accuracy and, as such, 

the ages assigned to landslides only provide an 

arbitrary indication of age. The WP/WLI (1990) 

regrouped the Varnes (1978) definitions on 

age and activity under the following headings: 

'state of activity,' 'distribution of activity' and 

'style of activity.' Whilst the NLD follows the 

style of activity definitions, it has simplified the 

state of activity terms defined by Varnes (1978) 

into active, inactive and stabilised whilst also 

adding descriptions on the state of development 

(Advanced, degraded, incipient). Whilst activity 

state and style have been described in the WP/ 

WLI definitions (WP/WLI, 1993), age has been 

somewhat neglected. Data for modern landslides 

observed either at the time of the event or through 

comparison of aerial photographs and geological 

mapping, is included in the NLD. To record cause, 

the NLD has incorporated both triggering and 

preparatory factors, limited to those most likely to 

be identifiable and relevant in GB. The definitions 

are based upon the WP/WLI (1990). 

Further adaptations of landslide susceptibility maps 

in Great Britain 

Following the creation of the Geosure 

methodology, BGS has worked within a 

consortium including the Transport Research 

Laboratory (TRL) and the Scottish Executive to 

create a digital hazard layer specifically for debris 

flows. This work was triggered in August 2004 

following a period of intense rainfall which led 

to two debris flows trapping 57 motorists on the 

A85 trunk road in Scotland. As a consequence 

of this event and others during the same period, 

the Scottish Executive commissioned a study to 

assess the potential impact of further debris flows 

on the transport network of Scotland (Winter et 

al., 2005). BGS was involved in the provision of a 

GIS layer highlighting slopes susceptible to debris 

flows. Debris flows, one of the five main types 

of landslides, have a specific set of preparatory 

criteria which differs from translational and 

rotational slides. This modified assessment 

sought to digitally capture this set of criteria and 

create a layer showing areas where debris flows 

are most likely to occur in the future. An initial 

study determined five main components which 

should be considered when determining the 

hazard potential of debris flows affecting the road 

network: 

1. Availability of debris material 

2. Hydrogeological conditions 

3. Land use 

4. Proximity of stream channels 

5. Slope angle 

It was considered that information regarding each 

of these could be extracted from existing digital 

datasets. The resulting interpreted data were 

combined to produce a working model of debris 

flow hazard that could be validated by comparing 

with known events (Fig. 2). The A85 debris flow 

event in 2004 is shown alongside the modelled 

susceptibility layer, existing drainage channels 

are shown as particularly susceptible to failure 

through debris flows. Whilst the assessment of 

debris flows highlights areas where they may 

occur in the future, it does not attempt to model 

the run-out of such failures. 

Future Developments 

Currently, work is ongoing to validate the current 

methodology against statistical methods such 

as bivariate statistical analysis and probabilistic 

methods. The GeoSure method is based upon 

expert knowledge and a heuristic approach 

which is being tested against more statistic-based 

approaches to assess its validity. Naranjo et al., 

(1994) consider statistical methods to be the 

most appropriate method for mapping regional 

landslide susceptibility because the technique is 

objective, reproducible and easily updateable. 

Bivariate analysis for instance relies upon the 

availability of landslide occurrence and causal 

parameter maps, which are compared against


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distributed data and causal factor information 

contained in the National Landslide Database of 

Great Britain, assesses the landslide susceptibility 

in Great Britain. It uses a heuristic approach to 

model the causative factors that cause these 

events. It assesses and classifies the propensity of 

a geological formation to fail as well as to score 

the relevant causative factors (e.g. slope angle). 

By using these methodologies and datasets, a 

national assessment of the potential hazard to 

landsliding mass movement events in Great 

Britain can therefore be undertaken. 

BIENIAWSKI Z T (1989). 

Engineering Rock Mass Classifications. Wiley Interscience, New York, 272 p 

BRITISH STANDARDS INSTITUTE. (1990). 

BS 5930. The Code of practice for site investigations. HMSO, London, 206 p 

EARLY, K.R. & SKEMPTON, A. 1972. 

Investigation of the landslide at Walton's Wood, Staffordshire. Quarterly 

Journal of Engineering Geology, 5, 19-41. 

FLAGEOLLET, J. C. (Ed) 1993. 

Temporal occurrence and forecasting of landslides in the. European 

Community. EPOCH (European Community Programme). 

FOSTER, C, GIBSON, AD & WILDMAN, G (2008). 

The new national landslide database and landslide hazards assessment 

of Great Britain. In: Sassa, K, Fukuoka, H & Nagai, H + 35 others (eds), 

Proceedings of the First World Landslide Forum, United Nations University, 

Tokyo. The International Promotion Committee of the International 

Programme on Landslides (IPL), Tokyo, Parallel Session Volume, 203-206. 

JORDAN, C. J., 2009. BGS∙SIGMAmobile; the BGS Digital Field Mapping 

System in Action. Digital Mapping Techniques 2009 Proceedings, May 10- 

13, Morgantown, West Virginia, USA, Vol. U.S. Geological Survey Openfile 

Report. 

Fig. 3a: Extract from the debris flow susceptibility layer along with 

b: the Glen Ogle debris flow of 2004. 

Abb. 3a: Ausschnitt der Gefahrenhinweiskarte für Muren, gemeinsam 

mit b: dem Murgang in Glen Ogle, 2004. 

each other to create a weighted value for each 

parameter determined by calculating the landslide 

density (Aleotti and Chowdhury, 1999 and Süzen 

and Doyuran, 2004). Results from an initial pilot 

study suggest that, in small areas, where detailed 

landslide mapping exists, bivariate (conditional 

probability) and probabilistic approaches are able 

to more accurately predict landslide susceptibility 

than GeoSure. However, this approach only 

works where landslides have been mapped. This 

technique cannot be used where no landslide 

mapping has been undertaken. Another issue 

with the conditional probability technique is that 

it relies on the assumption that all the parameters 

are mutually exclusive. The value of the heuristic 

approach is its ability to highlight areas where 

there are no known landslides but where there is 

existing knowledge on the underlying causative 

factors. The heuristic approach is able to produce 

national scale assessments which could be refined 

in the future by numerical methods for smaller, 

regional studies. 

Further adaptations to the GeoSure 

methodology, similar to those used to assess 

debris flows, are planned for the future. Rock fall 

hazard could be another type of mass movement 

that is investigated using the heuristic GeoSure 

approach applying different causal factors and 

scoring algorithms. 

Conclusion 

In Great Britain, landsliding does not have a 

structured regulatory framework, but historical 

events, such as the Aberfan disaster and Scottish 

debris flow events (Winter et al, 2005), have 

highlighted the importance of understanding 

the distribution and mechanisms that cause 

landslide mass movement events in Great Britain. 

The BGS GeoSure methodology, using spatially 


Dr. Helen J. Reeves 

Head of Science Land Use 

Planning & Development 

British Geological Survey, 

Kingsley Dunham Centre, 

Keyworth, Nottingham. 

United Kingdom, NG12 5GG. 

Direct Tel:- +44 (0)115 936 3381 

Mobile:- +44 (0)7989301144 

Fax:- +44 (0)115 936 3385 

E-mail:- hjre@bgs.ac.uk 


ALEOTTI, P., AND CHOWDHURY, R. 1999. 

Landslide hazard assessment: Summary review and new perspectives. 

Bulletin Engineering Geology and Environment, Vol. 58, pp. 21–44. 

ANON. (1990). 

Planning Policy Guidance 14: Development on Unstable Land. Department 

of the Environment, Welsh Office. Her Majesty's Stationery Office, London. 

ANON. (1994). 

Planning Policy Guidance 14 (Annex 1): Development on Unstable Land: 

Landslides and Planning. Department of the Environment, Welsh Office. 

Her Majesty's Stationery Office, London. 

Anon. (2004). The Building Regulations 2000 (Structure), Approved 

Document A, 2004 Edition. Office of the Deputy Prime Minister. Her 

Majesty's Stationery Office, London. 

CULSHAW, MG & KELK, B (1994). 

A national geo-hazard information system for the UK insurance industry 

- the development of a commercial product in a geological survey 

environment. In: Proceedings of the 1st European Congress on Regional 

Geological Cartography and Information Systems, Bologna, Italy. 4, Paper 

111, 3p. 

JORDAN, C. J., BEE, E. J., SMITH, N. A., LAWLEY, R. S., FORD, J., 

HOWARD, A. S., AND LAXTON, J. L., 2005. 

The development of digital field data collection systems to fulfil the British 

Geological Survey mapping requirements. GIS and Spatial Analysis: 

Annual Conference of the International Association for Mathematical 

Geology, Toronto, Canada, York University, 886-891. 

NARANJO, J.L., VAN WESTEN, C.J. AND SOETERS, R. 1994. 

Evaluating the use of training areas in bivariate statistical landslide hazard 

analysis: a case study in Colombia. International Institute for Aerial Survey 

and Earth Sciences. 3 : 292–300 

SKEMPTON, A. & WEEKS, A. 1976 

The Quaternary history of the Lower Greensand escarpment and Weald 

Clay vale near Sevenoaks, Kent. Philosophical Transactions of the Royal 

Society, A, 283, 493-526. 

SOETERS, R. & VAN WESTEN, C.J. 1996. 

Slope instability recognition, analysis and zonation. In: Transportation 

Research Board Special Report 247, National Research Council, National 

Academy Press, Washington, D. C., 129-177. 

SUZEN, M.L. AND DOYURAN, V. 2004. 

A comparison of the GIS based landslide susceptibility assessment methods: 

multivariate versus bivariate. Environmental Geology, 45, 665- 679. 

THE BUILDING AND APPROVED INSPECTORS REGULATIONS 

(Amendment). 2006. HMSO. 

TOWN AND COUNTRY PLANNING ACT. 1990. HMSO. 

VARNES D. J.: Slope movement types and processes. In: Schuster R. L. & 

Krizek R. J. Ed., Landslides, analysis and control. Transportation Research 

Board Sp. Rep. No. 176, Nat. Acad. oi Sciences, pp. 11–33, 1978. 

WALSBY, JC (2007). 

Geohazard information to meet the needs of the British public and 

government policy. Quaternary International, 171/172: 179-185. 

WALSBY, JC (2008). 

GeoSure; a bridge between geology and decision-makers. In: Liverman, 

D.G.E., Pereira, CPG & Marker, B (eds.) Communicating environmental 

geoscience. Geological Society, London, Special Publications, 305: 81-87. 

WINTER, M. G., MACGREGOR, F & SHACKMAN, L (Eds) 2005. 

Scottish Road Network Landslides Study. The Scottish Executive. Edinburgh. 

WP/ WLI. 1993. 

A suggested method for describing the activity of a landslide. Bulletin of the 

International Association of Engineering Geology, No. 47, 53-57. 

WP/ WLI. (International Geotechnical Societies UNESCO Working Party on 

World Landslide Inventory) 1990. 

A suggested method for reporting a landslide. Bulletin of the International 

Association of Engineering Geology, No. 41, 5-12.


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KARL MAYER, BERNHARD LOCHNER 

International Comparison: Summary of the Expert 

Hearing in Bolzano on 17 March 2010 

Internationaler Vergleich: Zusammenfassung 

des Expert Hearings in Bozen vom 17. März 2010 


Das AdaptAlp Workpackage 5 „Expert Hearing“ am 17. März 2010 in Bozen wurde von 28 Experten 

aus acht Ländern besucht und widmete sich inhaltlich vollständig den Zielen von Action 

5.1: Der Aufbau eines mehrsprachigen Glossars zu Hangbewegungen und insbesondere die 

Erarbeitung von Mindestanforderungen zur Erstellung von Gefahrenkarten. Neben einer kurzen 

Vorstellung des Projektfortschrittes und der weiteren Vorgehensweise hinsichtlich der Erarbeitung 

eines mehrsprachigen Glossars wurde von Vertretern aus allen beteiligten Ländern der jeweilige 

„State oft the Art“ bezüglich Gefahrenkartierung vorgestellt. Ausgehend von diesen Präsentationen, 

welche die Grundlage für das weitere Vorgehen bilden, wurden im Anschluss an das Treffen 

Kurzzusammenfassungen für jede Region verfasst, welche innerhalb eines Gesamtberichtes auf 

der AdaptAlp Homepage (www.adaptalp.org) einzusehen sind. In einem weiteren Schritt wurden 

auf Basis dieser Beiträge zwei Tabellen erstellt, welche einerseits alle verwendeten Karten 

strukturiert nach verschiedenen Typen und andererseits unterschiedliche Charakteristiken von 

Karten zusammenfassen und auf Länderebene vergleichen. Mithilfe dieser Matrizen werden Gemeinsamkeiten 

und Unterschiede zwischen den beteiligten Regionen sichtbar und ein „kleinster 

gemeinsamer Nenner“ kann erarbeitet und in einem nächsten Meeting (Dezember 2010) fixiert 

werden. Ergebnis dieses Vorgehens und des Projektteiles wird eine Zusammenstellung von Mindestanforderungen 

zur Erstellung von Gefahrenhinweiskarten und Gefahrenkarten sein. 

Summary: 

The AdaptAlp work package 5 “Expert Hearing” on March 17th, 2010 in Bolzano was 

attended by 28 experts from eight countries. It was dedicated to the goals of action 5.1: The 

creation of a multilingual glossary on landslides and especially the elaboration of minimum 

requirements for “hazard mapping”. Beside a short presentation on the progress and the 

further approach of the multilingual glossary, the “state of the art” in hazard mapping 

for each involved region was presented by several people responsible. Based on these 

presentations, which build the basis for the further approach, short abstracts were composed 

for each region. These short descriptions can be seen inside the official Hearings report 

published on the AdaptAlp Homepage (www.adaptalp.org). In a further step, based on these 

abstracts and the presentations, two tables were created. On the one hand, all used maps 

were grouped according to different types and on the other hand diverse characteristics of 

maps were summarized and compared at the country level. With these matrices, similarities 

and differences between the involved regions become visible and a “least common 

denominator” could be elaborated. These denominators should be discussed at the next 

meeting (December 2010) and, as a result, a compilation of minimum requirements to the 

creation of “Danger, Hazard and Risk maps” will be published. 


In dealing with geological hazards today, 

geotechnical (active) and spatial (passive) 

measures come to implementation to minimize 

risk. Because of a time limitation of active 

measures (e.g. protective walls) and the decrease 

of space for permanent settlings, spatial planning 

gets more and more important. Due to avalanche 

catastrophes in the 1950’s which were affecting 

large parts of the Alps, in 1954 in the Swiss 

municipal Gadmen, the first “Avalanche-Zone- 

Plan” was passed. This was the first time a natural 

hazard was considered in spatial planning (cf. 

Glade a. Felgentreff 2008, p 160f). 

Nowadays, almost 60 years later, “hazard 

mapping” is a central part in risk management. 

Countless types of “Danger, Hazard and Risk 

maps” are produced for all kinds of risks. With 

regard to natural hazards, especially geological 

processes, a large variety of maps and methods 

are used in the different European countries to 

prevent natural disasters. 

Exactly this variety, which reaches 

from simple danger mappings to legally binding 

“Hazard Zone Plans” (Gefahrenzonenplan), 

should be shown inside this part of the AdaptAlp 

project. However main goal of work package 5 

(WP 5) is not only the description of this variety, but 

a development of a “least common denominator” 

which includes the minimum requirements for the 

creation of Danger, Hazard and Risk maps. 

This article focuses on the AdaptAlp 

“Expert Hearing” from 17 March 2010 take place 

in Bolzano and which dedicates the contents of 

work package 5. In the following sections, the 

main goals of this meeting and the contributions 

from the involved experts were shown. In the 

final chapter, first basic approaches concerning a 

possible synthesis out of the big variety of “hazard 

planning methods” is pointed out.


Seite 160 

Seite 161 

2. Main goals of the “Expert Hearing” 

The topics of the expert hearing are all about the 

goals of the AdaptAlp Work package 5 – “Hazard 

Mapping”: 

“Hazard zones are designated areas 

threatened by natural risks such as avalanches, 

landslides or flooding. The formulation of these 

hazard zones is an important aspect of spatial 

planning. AdaptAlp will evaluate, harmonise and 

improve different methods of hazard zone planning 

applied in the Alpine area. Focus will be on a 

comparison of methods for mapping geological 

and water risks in the individual countries. A 

glossary will facilitate transdisciplinary and 

translingual cooperation as well as support the 

harmonisation of the various methods. In selected 

model regions, methods to adapt risk analysis to 

the impact of climate change will be tested. This 

should support the development of hazard zone 

planning towards a climate change adaptation 

strategy. The results will be summarized in a 

synthesis report (www.adaptalp.org). 

The official description of WP 5 shows 

two main parts (goals), which are worked out in 

Action 5.1 under the leadership of the Bavarian 

Environment Agency (LfU) in collaboration with 

the alpS – Centre for Natural Hazard and Risk 

Management in Innsbruck and with the inputs 

from the international experts of the project 

partners. 

The two main goals are the elaboration 

of a “multilingual glossary to landslides” and the 

development of “minimum standards to create 

danger, hazard and risk maps”. 

As announced in the introduction, 

the main focus of the hearing in Bolzano lies 

on the elaboration of basics for the definition 

of minimum standards for hazard mapping. 

Therefore the progress of the glossary was only 

addressed inside a short presentation at the 

beginning of this meeting. The rest of this one-day 

session was dedicated to the contents of hazard 

mapping. Due to this and the fact that the glossary 

part is already described in detail within chapter 

2.6 of this publication, this article only refers to 

the hazard mapping part. 

3. Hazard mapping in the Alpine regions 

At the beginning of this chapter, it is important 

to clarify that, because of the scheduled timing 

of the project, at this time no final results can be 

presented. Nevertheless, the theoretical approach 

and the already achieved marks can be shown. In 

general the course of action in getting a “synthesis” 

to hazard mapping is structured in three steps. 

First step is the evaluation of the “state of the art” 

in hazard mapping in each country involved. 

Exactly this point was the intention and the 

main goal of the hearing in Bolzano. Two main 

questions remained to be answered: 

• What kinds of danger, hazard and risk maps 

are officially applied in each country? 

• Which standards are these maps based on? 

To answer these questions, each participant gave 

a short overview of the official used danger, 

hazard and risk maps and also information on 

the creation of such maps were given in short 

presentations. 

The second step will be the 

“harmonisation” of the different methods used in 

several countries. Therefore similarities should be 

worked out and the “least common denominator” 

in the methods of hazard mapping should be 

found. This second step is to be discussed in detail 

in the next workshop at the end of 2010. 

The final part will be the creation 

of a report, which includes the results of this 

“harmonisation”. Within the hearing in Bolzano, 

the plenum discussed the possible commitment 

of such a report for each country. However the 

title of the project contained the term “minimum 

standards”, which rather sounds like a legal 

term, the involved experts decided to switch to 

word standards with “requirements”. So this legal 

character is avoided and the final report will 

include a part with “minimum requirements to the 

creation of danger, hazard and risk maps”. 

4. Short summary from the “expert-contributions” 

in Bolzano 

In the following sections, the “state of the art - 

presentations” from several experts in Bolzano are 

shown in short summaries for each country. 

4.1 Germany 

In Germany, geogenic natural hazards, such 

as mass movements, karstification, large scale 

flooding, as well as building ground that is 

affected by subsidence and uplift, shall in future 

be recorded, assessed and spatially represented 

using a common minimum standard. An 

important component for developing danger maps 

is the construction and evaluation of landslide 

inventories (e.g. landslide or sinkhole inventories). 

The recorded data in the inventories should have a 

minimal nationwide standards and are divided into: 

• Main data on the topic area mass 

movements and subrosion / karst with 

information about the spatial positioning, 

about determination of coordinates, etc. 

• Commonly shared technical data of 

the subject area mass movements and 

subrosion / karst with information about 

the date of origin, about the land use and 

about damage, etc. 

• Specific technical data of the subject area 

mass movement and subrosion / karst 

• Surface data concerning subsidence and 

uplift 

Regarding landslides, slide, fall, flow and 

subrosion processes are recorded in the 

inventories. Methods lasting from field studies to 

computerized modelling are used for the creation 

of these “danger maps”. In Germany, danger 

maps serve as a first estimation of possible natural 

hazards caused by certain geological conditions 

and should serve as a planning reference for 

possible investigations of individual objects where 

necessary. On the danger map, the areas in which 

natural hazards are possible are not delineated 

precisely and local conditions (e.g. prevention 

schemes, topographic peculiarities) are not taken 

into consideration in every case. Because of these 

reasons, it is recommended adding the following 

annotations for each subject area: 

“The following map was created for a 

1:25,000 scale and is not precise. It serves as a 

first estimation of possible engineering geological 

hazards and cannot replace a geotechnical 

survey. Areas within the immediate vicinity of 

danger fields can also be affected. The intensity 

and probability of a possible event cannot be 

extracted from the map.” 

4.2 Austria 

At this time there is no regulatory framework or 

technical norm concerning mass movements in 

Austria. Only the course of actions concerning 

floods, avalanches and debris flows are regulated 

by law. This includes the generation of “hazard 

zoning maps” (“Gefahrenzonenplan”). These are 

generated by the Austrian Service for Torrent and 

Avalanche Control (Forsttechnischer Dienst für 

Wildbach- und Lawinenverbauung, WLV).


Seite 162 

Seite 163 

As there are no legal instructions or standards 

in Austria about if or how to deal with the 

evaluation of mass movements, the federal states 

are all following a different course of action. 

The status of available data is very different in 

the individual states. In some of the federal 

states almost no data is available, others have a 

lot of data but not digitally available. And then 

there are states that can rely on a lot of digitally 

available data and are working on generating 

landslide susceptibility maps. 

4.3 Italy (Piemonte, Emilia-Romagna, Province Bolzano) 

In Italy the national law (high level, n. 445/1908) 

and Royal Decree R.D. (n. 3267/1923) were the 

first public regulations on land use planning. At 

the beginning of ‘70s the land use management 

was transferred to regions. 

The national Law n. 183/1989 

introduced land use planning at a basin scale. 

The government sets the standards and general 

aims without fixing a methodology to analyse and 

evaluate the dangers, hazards and risks related 

to natural phenomena. The same law designated 

the Autorità di Bacino (Basin Authority) whose 

main goal is to draw up the Basin Plan, a tool for 

planning actions and rules for conservation and 

protection of the territory. 

One of the available tools produced by 

ARPA Piemonte is the Italian Landslides Inventory 

(IFFI). It is a national program of landslides 

inventory, sponsored by national authorities and 

made locally by the regions. It is the first try of 

an inventory based on common graphical legend 

and glossary. 

The Emilia-Romagna Landslide Inventory 

Map (LIM) reports over 70,000 landslides, while 

the historical data base contains about 6,600 

landslide events. LIM may be considered as an 

elementary form of a hazard map and, based 

on this, enforce rules and obligations addressing 

landslide hazard reduction: only existing hamlets 

and villages can extend on dormant landslides; 

on active ones, all new construction is forbidden. 

Otherwise, the use of a purely descriptive 

terminology (active, dormant), restricts the 

usability of this map, being often obsolete, and is 

therefore a frequent bone of contention. 

In the federal state law from 11 August 

1997, the base for the approval of guidelines to the 

creation of hazard plans (Gefahrenzonenpläne) for 

South Tyrol was laid. Also the role of municipalities 

was defined to carry out the planning within 

three years. Finally, the approval of plans and the 

role of coinvolved partners are also part of this 

law. The scale of this legal binding hazard plan 

(“Gefahrenzonenplan”) in South Tyrol tends to the 

working level of detail for the analyzed area. In 

settlements, a 1:5,000 scale and in other regions a 

1:10,000 scale is used and landslides, hydrological 

hazards and avalanches are analyzed. 

4.4 Switzerland 

Switzerland is a hazard-prone country exposed 

to many mass movements, but also to floods and 

snow avalanches. Active and dormant landslides 

take some 6% of the national surface. Most of the 

landslides are very slow or slow reaching some 

millimetres to centimetres of displacement per 

year. Sudden slope movements with velocities up 

to 40 m/s are also observed (e.g. rock avalanches). 

The federal laws came into force in 1991 and are 

based on an integrated approach to protect people 

and property from natural hazards. The nontechnical, 

preventive measures are of particular 

importance: land-use planning, zoning, building 

codes. The reference documents in Switzerland 

are the natural hazard maps. The techniques 

for developing these maps are outlined in the 

federal guideline where a three step procedure is 

proposed: 

1) Firstly, an indispensable prerequisite for the 

landslide hazard identification is obtaining 

information about past slope failure events: 

the maps of phenomena and the registration 

of events (database). 

2) Secondly, hazard assessment implies the 

determination of magnitude or intensity 

over time. Five classes of hazard are 

determined in Switzerland: high danger 

(red zone), moderate danger (blue zone), 

low danger (yellow zone), residual danger 

(yellow-white zone) and no danger (white 

zone). 

3) Based on the hazard maps and risk analysis, 

three kinds of measures can be then taken 

(third step): planning measures, technical 

measures and organizational measures. 

4.5 France 

The plan for prevention of natural hazards (plan 

de prévention des risques naturels prévisibles - 

PPR) established by the law of 2 February 1995 

is the “central” tool of the French State's action 

in preventing natural hazards. The elaboration 

of the PPR is conducted under the authority of 

the prefect of the department, which approves it 

after formal consultation of municipalities and a 

public inquiry. The PPR is achieved by involving 

local and regional concerned authorities from the 

beginning of its preparation. It can handle only 

one type of hazard or more and cover one or 

several municipalities. 

In the frame of this common procedure, 

a general methodological guidelines document 

has been published. One of these guideline 

documents is dedicated to geological hazards, 

which includes subsidence, sinking, collapse, 

rock falls, landslides, and associated mud flows, 

but excludes debris flows. 

4.6 England 

Up until 1966, the UK Government were not 

interested in Geohazards, they were more 

interested in finding oil and gas to help the UK 

economy develop and expand. After the Aberfan 

disaster (where 144 people, 116 of them children), 

the UK government were much more interested 

and funded a number of research projects to look 

at the UK’s geohazards. 

An inventory is the first step in 

building an understanding of the occurrence of 

geohazards. Currently BGS maintains two main 

shallow geohazard databases: the National 

Landslide and Karst Database (www.bgs.ac.uk). 

These inventories provide the basis for analysing 

the spatial distribution of the geohazard and 

their causal factors. From this understanding 

susceptibility can be assessed. In 2002, BGS 

developed a nationwide susceptibility assessment 

of deterministic geohazards such as landslides, 

skrink-swell, etc. called GeoSure (http://www.bgs. 

ac.uk/products/geosure/). 

4.7 Spain (Catalonia) 

The Parliament of Catalonia approved, with Law 

19/2005, the creation of the Geological Institute 

of Catalonia (IGC), assigned to the Ministry 

of Land Planning and Public Infrastructures 

(DPTOP) of the Catalonian Government. The 

most important mapping plan is the Geological 

Hazard Prevention Map of Catalonia 1:25,000 

(MPRGC25M). As a component of the 

Geoworks of the IGC, the strategic program


Seite 164 

Seite 165 

Comparison of different maps and their scales 

Austria Germany Switzerland Slovenia Italy France Spain UK 

Level Type of map GBA and Kärnten WLV Bayern CH Slovenia 

basic 

inventory 

Arpa 

Piemonte 

South Tyrol 

Emilia 

Romagna 

France Catalonia UK 

Geomorphologic map large scale variable scales 1:10,000 1:5,000 1:10,000 1:10,000 variable 

Geotechnical map 1:5,000-1:50,000 1:200,000 

Engineering geological map 1:5,000 (landslides) 1:250,000 

Level of attention 

Inventory map 1:25,000 to 1:50,000 

Multi-temporal inventory map 

1:5,000 to 1:2,000 

and 1:25,000 to 

1:50,000 

1:10,000- 

1:25,000 

1:10,000-1:50,000 

(M1), 1:2,000- 

1:10,000 (M2), 

1:5,000-1:2,000 or 

bigger (M3) 

Municipal 

>1:50,000 1:10,000 1:10,000 1:25,000- 

1:100,000 1:10,000 1:25,000 

- 

1:10,000 

Map of phenomena 

1:50,000 and bigger 

1:10,000-1:50,000 

(M1), 1:2,000- 

1:10,000 (M2), 

1:5,000-1:2,000 or 

bigger (M3) 

1:10,000 

1:5,000 or 

1:10,000 

variable 

scales 

1:25,000 

and bigger 

1:10,000- 

1:50,000 

suscepti-bility 

Map of area of activity 1:25,000 1:10,000 

Landslide susceptibility 

map, danger map 

(Gefahrenhinweiskarte) 

1:200,000 (K, regional), 

1:50,000 (St., local) 

1:25,000 1:10,000-1:50,000 1:250,000 1:10,000 yes 

1:25,000 

(2000) 

1:5,000 

(2009) 

1:10,000- 

1:50,000 

1:25,000 1:50,000 

hazard index map K, Bleiberg: 1:10,000 

Hazard map 1:2,000-1:10,000 1:25,000 

1:10,000- 

1:25,000 

1:25,000 


Detailed Study (Detailstudie) 

Hazard zone map 

(Gefahrenzonenkarte) 

not smaller than 

1:50,000, usually 

1:2,000 to 1:5,000 

1:5,000-1:2,000 or 

more 

1:10,000 

1:5,000; 

1:10,000 

1:5,000 - 

1:1,000 

Hazard zone map of the 

development plan 

1:10,000 

1:5,000; 

1:10,000 

1:5,000 

Map of potential damage 

1:5,000; 

1:10,000 

risk 

Vulnerability map 1:250,000 

Risk zoning map, risk map 

1:5,000; 

1:10,000 

Fig. 1: Comparison of different maps and their scales 

Abb. 1: Vergleich unterschiedlicher Karten und deren Maßstab


Comparison of information collected for different inventories 

Characteristics Austria Ger CH SLO Italy F UK ES 

GBA K By CH SLO EmRo AP ST F UK Catalan 

Inventory x x x x x x x x x x 

national scale x x x x x x 

regional scale x x x x x 

study/ detailed scale x x x 

geometry (width, length...) x x x x x x x x x x x 

Basic information where x x x x x x x x x x x 

when x x x x x x x x x x x 

what x x x x x x x x x x x 

why x x x x x x x x x 

who x x x x x x x x x 

reported when x x x x x x x 

Landslide conditions activity ( number of events...) x x x x x x x x x x x 

slope position x x x x x x x 

approx. original slope x x x 

positional accuracy x x x 

site description x x x x x x 

depth to bedrock x 

depth to basal failure plane x x 

slope aspect x x x x x x x x 

slope x x x x x x 

Geology in general x x x x x x x 

Geology, specified geologic unit x x x x x x x 

tectonic unit x x x x 

lithology x x x x x x x x 

stratigraphy x x x x 

bedding attitude x x x 

weathering x x x 

geotechnical properties (rock, debris) x x x x x x 

geotechnical parameters (shear,…) x x 

rock mass structure x x x x 

joints x x 

joint spacing x 

discontinuities x 

structural contributions x x 

Land cover x x x x 

Land use x x x x 

Hydrogeology x x x 

Relationship to rainfall x x 

Classification of mass movements (not specified) x x x x 

Classification type x x x x x x x x x x 

rate of movement x x x x x 

material x x x x x x 

water content x x x 

Causes x x x x x x x x x x 

Trigger x x x x x x 

Precursory signs (fissures,…) x x x 

Silent witnesses x x 

Rock fall: shadow angle x x x 

Rock fall: (geometric) slope gradient x x x 

Damage x x x x x x x x x x 

"Hazard" to infrastructure x x x x x 

Remedial measures x x x x x x x 

Costs of rem. Measures x x x 

Costs of investigation x 

Method used to gather info (field survey, aerial photo-interpretation,…) x x x x x x x x x 

Degree of precision of information x x x x x x 

Certainty/ reliability of information x 

Investigations, reports, documentation, references included x x x x x x x x 

Bibliography included x x x x x x 

Fig. 2: Comparison of characteristics and information collected for different inventories and maps 

Abb. 2: Vergleich von Charakteristiken und eingehende Informationen für unterschiedliche Inventare und Karte 

Seite 166 

Seite 167


Seite 168 

Seite 169 

aimed to acquiring, elaborating, integrating and 

disseminating the basic geological, pedological 

and geothematic information concerning the 

whole of the territory in the suitable scales for 

the land and urban planning. This project started 

in 2007. In the MPRGC, evidence, phenomena, 

susceptibility and natural hazards of geological 

processes are represented. These processes are 

generated by external geodynamics (such as slope, 

torrent, snow, coastal and flood dynamics) and 

internal (seismic) geodynamics. The information 

is displayed by different maps on each published 

sheet. The main map is presented on a scale of 

1:25,000, and includes landslide, avalanche 

and flood hazard. Hazard level is qualitatively 

classified as high (red), medium (orange) and low 

(yellow). The methods used to analyze hazards 

basically consist of geomorphologic, spatial and 

statistical analysis. 

4.8 Slovenia 

Legislation, planning and prevention measures are 

not satisfying in the field of landslides in Slovenia 

and the primary activities are still focused on 

remediation instead on the prevention measures. 

The updated Act on Spatial planning from 

2007, governing natural disasters also discusses 

problems with mass movements, but a common 

methodology and procedures to prevent geologyrelated 

natural disasters does not exist yet. 

At the moment for Slovenia, a 

“landslide susceptibility map” (scale 1:250,000) 

and a “debris-flow susceptibility map” (scale 

1:250,000) is elaborated by the Geological Survey 

of Slovenia. In addition to this, a probabilistic 

model of slope mass movement susceptibility for 

the Bovec municipality in north-western Slovenia 

was developed based on the expert geohazard 

map at scale 1:25,000 and several other relevant 

influence factors. 

5. Conclusion 

As mentioned in the introduction of this article, 

the “state of the art in hazard mapping“ in the 

involved countries isn’t in balance. This fact was 

also confirmed inside the “Expert Hearing” in 

Bolzano. 

To solve this problem, in a first step the 

big variety of maps applied in the several regions 

was summarized in one table (see Fig. 1). This chart 

builds the basis for further actions concerning 

the creation of minimum requirements. It is 

structured into different levels and the associated 

type of maps. The levels lasting from “basic” (e.g. 

geomorphologic maps) over “inventories” (e.g. 

inventory map), “susceptibility” (e.g. susceptibility 

map) and “hazard” (e.g. hazard map) to “risk” 

(e.g. risk map). 

Furthermore, a matrix (see Fig. 2) 

with specified characteristics and information 

collected for different maps was created out 

of the great wealth of information given at the 

hearing in Bolzano. In particular, this table should 

help to find accordance’s between the different 

approaches. All the characteristics used in any 

involved country (e.g. inventory) form the basis 

for the definition of minimum requirements to 

“hazard mapping”. 

Finally, out of these two matrices a 

recommendation will be created and, based 

thereon, the final minimum requirements should 

be fixed in the next workshop on December 2010 

in Munich. The final report on the whole project 

will include a chapter with the decided minimum 

requirements to the creation of “Danger, Hazard 

and Risk maps”. 


Karl Mayer 





Bernhard Lochner 

alpS – Centre for Natural Hazard and Risk 

Management 

Grabenweg 3 

6020 Innsbruck - AUSTRIAText 


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FELGENTREFF, C. & GLADE, T. (Hrsg.) (2008): Naturrisiken und 

Sozialkatastrophen. Spektrum Akademischer Verlag, Heidelberg, 454 S. 

KOMAC, M. (2005): Probabilistic model of slope mass movement 

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Seite 170 

AdaptAlp 

DI Maria Patek, MBA 


Umwelt und Wasserwirtschaft 

Abteilung IV/5 

Marxergasse 3 

1030 Wien 

Tel.: 01/711 00 - 7334 

Fax: 01/71100 - 7399 

E-Mail: die.wildbach@lebensministerium.at

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