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Landslide VulnerabilityThe degree of loss resulting from the occurrence of a landslide of a given magnitude (Varnes, 1984)LandslipA synonym for “landslide” – the term “Landslip” no longer in much usageMass MovementMovement of a portion of the land surface, usually downslope – a general descriptive termMoraineA mound, ridge, or other distinct accumulation of unsorted, unstratified glacial drift deposited by (former) icesheets and glaciersMudFine-grained soils dominated by material of clay to sand-size, in a wet condition. < 2mm in diameterOrogenyThe process of the formation of mountains and more specifically the process by which structures in fold-belt mountains wereformed – folding, thrusting, faultingPeriglacialAn environment in which frost action is an important factor, or phenomena induced by a periglacial climate beyond the periphery ofthe icesheetPermafrostAny soil or subsoil occurring in arctic, sub-arctic, or alpine regions which has been frozen continuously for a long timeQuaternaryThe upper system of the Cenozoic Era beginning 2.3 million years ago and which forms the current period of geological time. It is madeup of the Pleistocene (Ice Age) and the Holocene (Postglacial ) EpochsRaised BogAn accumulation of peat with its greatest thickness being at the centre giving it a convex-upward surface. They are found in themidlands of Ireland and are principally composed of moss peatRaster imageAn image composed of a rectangular grid of pixels. Each pixel contains a defined value about its colour, size, and location in theimage.RegolithThe layer of fragmented and unconsolidated rock material overlying the bedrockScreeRock fragments, usually coarse and angular, derived from and lying at the base of cliffs or very steep slopesShear StrengthThe internal resistance of a body to shear stress, typically including a frictional part and a part independent of friction called cohesionSlickensidesA lineated fault or slip surface, having groove lineations which may indicate the direction of slippage on the surfaceSlideA mass movement of earth material under shear stress along one or several surfaces. The movement may be rotational or planar(translational)SolifluctionThe slow viscous downslope flow of waterlogged soil, usually in areas underlain by frozen ground ie. in periglacial areasSpreadThe dominant movement in a spreading landslide is lateral extension due to shearing or tensional fracturesTalusSee “Scree”TillLargely unsorted and unstratified material deposited directly underneath a glacier and consisting of a heterogeneous mixture of clay,silt, sand, gravel, and bouldersToppleA mass movement that consists of the forward rotation of units of rock about a pivot point under the force of gravityTsunamiA gravitational seawave produced by any large-scale, short duration disturbance of the sea-floor due to an earthquake, sea floorsubsidence or a volcanic eruption98
APPENDIX 3Nomenclature for Landslides (Anon, 1990)Bull. Int. Ass. Eng. Geol., 41, 13 - 16Landslide FeaturesCrown (1)The practically undisplaced material still in place and adjacent to the highest parts of the main scarp.Main scarp (2)A steep surface on the undisturbed ground at the upper edge of the landslide, caused by movement of the slide material awayfrom the undisturbed ground.Top (3)The highest point of contact between the displaced material (13) and the main scarp (2).Head (4)The upper parts of the landslide along the contact between the displaced material and the main scarp (2).Minor scarp (5)A steep surface on the displaced material of the landslide, produced by differential movements within the sliding mass.Main body (6)The part of the displaced material of the landslide that overlies the surface of rupture between the main scarp (2) and the toe ofthe surface of rupture (11).Foot (7)The portion of the landslide that has moved beyond the toe of the surface of rupture (11) and overlies the original groundsurface.Tip (8)The point of the toe (9) farthest from the top (3) of the landslide.Toe (9)The lower, usually curved margin of the displaced material of a landslide, it is the most distant from the main scarp (2).Surface of rupture (10)The projection of the main scarp (2) surface under the displaced material of a landslide.Toe of surface of rupture (11)The intersection (sometimes buried) between the lower part of the surface of rupture (10) of a landslide and the original groundsurface.Surface of separation (12)The part of the original ground surface overlain by the foot (7) of the landslide.Displaced material (13)Material displaced from its original position on the slope by movement in the landslide.Zone of depletion (14)The area of the landslide within which the displaced material (13) lies below the original ground surface.Zone of accumulation (15)The area of the landslide within which the displaced material lies above the original ground surface.99
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Landslides in IrelandGeological Sur
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LANDSLIDESinIRELANDEditorRonnie Cre
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CONTENTSPreface ...................
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Fig. 4.3 Forces caused by water in
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PREFACEUntil recently Ireland has b
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een very important in populating th
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involves a report on the current st
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Main Objectives• Increase public/
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1. INTRODUCTIONRonnie Creighton1.1
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1.3 The Landslides PublicationThis
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Peat flows are not nearly so well d
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In Ireland the Quaternary or uncons
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Journal - published papersLetter -
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Fig. 3.1 Two images showing the use
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Table 3.1 Landslide Events Per Coun
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Fig. 3.3 Location map of the Pollat
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3.7.4 Quaternary GeologyQuaternary
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3.8 The Derrybrien Landslide - 2003
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• The classification scheme shoul
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The force causing the block to slid
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Plate 4.1 Herringbone drainage syst
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1210Number of events864Raised bogBl
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It is well known by research at Uni
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5. LANDSLIDE SUSCEPTIBILITY MAPPING
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Two simplified hypothetical example
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5.1.4 Mapping and GISBy definition,
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Platform / sensor pixel resolution(
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For this initial run, the criteria
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42Fig. 5.5 Peat and peaty podzols f
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for susceptibility mapping purposes
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elationships between developed susc
Page 64 and 65: The methodology used to derive the
Page 66 and 67: 50Fig. 5.12. Landslide susceptibili
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Page 72 and 73: with slope, overall 20-25% of all e
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Page 79 and 80: CHAPTER 5.2 - TABLE APPENDIXBedrock
Page 81 and 82: 6. LANDSLIDES AND PLANNINGAileen Do
Page 83 and 84: 6.2.4 Development ManagementThe phy
Page 85 and 86: 6.5 Current Practice on Landslides
Page 88 and 89: 7. LANDSLIDES IN NORTHERN IRELANDTe
Page 90 and 91: 2. MudflowsPlate 7.1 Rotational Lan
Page 92 and 93: 7.2 Carboniferous Cliff Lines (Co F
Page 95 and 96: 8. RESEARCH ON IRISH LANDSLIDESKoen
Page 97 and 98: 8.4 Research. Post-2003 AbstractsTa
Page 99 and 100: Identifying, recognizing, and predi
Page 101 and 102: In the case of vulnerability mappin
Page 103 and 104: Steep slopes in glacial tillMichael
Page 105 and 106: 9. RECOMMENDATIONS FOR FUTURE WORK9
Page 107 and 108: Priority 1 Peat slides and peat str
Page 109 and 110: TEXT REFERENCESAcreman, M., 1991. T
Page 111 and 112: Skipper, J., Follett, B., Menkiti,
Page 113: APPENDIX 2Glossary of TermsBlanket
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Page 123 and 124: Hammond, R. 1979. The Peatlands of
Page 125: APPENDIX 7Useful Web Linkswww.gsi.i
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