Hard lessons for hazard, risk and socio-economic impacts of the ...

Observations from Canterbury Reinforce GEM’s Vision 

Kelvin Berryman – Director, Natural Hazards Research Platform, New Zealand 

22 Feb, 2011 

GEM semi-annual meeting, Taipei, June 2012 

Natural Hazards Research GNS Science Platform

An update on the Canterbury earthquake 

sequence and possible insights for GEM 

• Characteristics of the earthquake sequence and impacts 

• Characteristics of the city and regional economy 

• Response and recovery actions – role of government 

• Socio-economic insights 

• Rebuilding a more resilient city 

• Rebuilding – impediments and opportunities 


Natural Hazards Research GNS Platform Science



An update on the 

Canterbury earthquake sequence 

• The regional context 

• The continuing aftershocks: their frequency and strength 

• Why was there so much damage to the Canterbury region in 

Feb 2011 and subsequently 

• Earthquake forecast probabilities – what do they mean 

Hazard in Canterbury is moderate by NZ standards –10% in 50 yr PGA of ~ 0.3 g 



How normal or abnormal is the sequence 



Ground Shaking 



Features of the earthquake sequence in the NZ context 

A large (for NZ) natural hazard event in a small economy 

• 10% of NZ’s 4.5 million people directly impacted 

• Total loss estimates c. $30b NZD – about 8-10% GDP 

• NZ’s economy about the same size as Munich-Re or IBM annual revenue 

Events such as this have the possibility of irreparably damaging the economy 

of small or developing nations 

Regional economy is strong (based on agriculture) 

• Port, airport, road and rail networks had very little downtime 

• 95% of businesses are still operating albeit with downturn in tourism, education, 

and hospitality 

• Some migration away from Canterbury especially initially, now about 10,000 

persons, but 30,000 new workers needed for rebuild – communities remained 

largely intact, even in the “residential red zone” 

• Early government support for local business continuity 

A city cannot operate in isolation from its hinterland. Supply chains and 

infrastructure are critical. There was no need for widespread evacuation in 

Christchurch and this is a key tipping-point in regional economic resilience 



Canterbury Community Resilience 



An extended sequence of events 

4 September 22 February 13 June 13 23 December 

2010 2011 2011 2011 

Mag (M w ) 7.1 6.2 6.0 5.9 

Epicentre 1 30 km W 10 km SE 10 km SE 10 km E 

Time 2 4:36 am 12.51 pm 2.20 pm 3.18 pm 

Max PGA 3 0.6g (0.3g CBD) 2.2g (0.8g CBD) 2.2g (0.4g CBD) 0.96g 4 (0.25g CBD) 

Casualties 0 fatalities 185 fatalities 0 fatalities 0 fatalities 

Building 

Damage 

To older concrete 

& URM 

Liquefaction Widespread in 

eastern suburbs 

All pre-1970’s & 

several modern 

buildings with 

eccentric design 

Extreme damage in 

many eastern 

Christchurch 

suburbs 

Further residential 

damage in Port 

Hills & already 

damaged CBD 

buildings 

Further damage 

in eastern 

Christchurch 

suburbs 

Minor, but several 

instances of 

progressive failure 

Minor damage in 

eastern 

Christchurch 

suburbs 

Cost 5 4-5 billion 15-20 billion c. 1.5 billion c. 26 million 

• Long and evolving impacts – more like an extended volcanic eruption 

• On-going social impacts – psycho-social issues, confidence, domestic violence 

• Progressive degradation of the built environment 

• Pessimistic insurance and reinsurance markets 



Insurance Perspectives - Recent major earthquake events 

USD billion (at 2011 prices) 

Event Date Country Economic Economic losses Insured Insurance 

Losses as %GDP Losses Industry 

Contribu:on 

11 March 11 Japan up to 300 up to 5.4% 35 up to 17% 

27 Feb 11 Chile 30 18.6% 8 27% 

22 Feb 11 NZ 15 10% 12 80% 

!2 Jan 10 Hai: 8 121% 0.1 1% 

04 Sept 10 NZ 6 5.3% 5 81% 

06 April 09 Italy 4 0.2% 0.5 14% 

23 Oct 11 Turkey 0.75 0.1% 0.03 

4% 

04 April 10 Mexico 0.95 0.09% 0.2 21% 

Source: Swiss Re sigma catastrophe database 

NZ presents the highest ratio of insured to economic losses. Residential earthquake 

insurance virtually mandatory through the EQ Commission, so insurance plays a 

much greater role in reconstruction efforts than in other examples 



central Government actions 

Long term 

• National residential insurance programme (Earthquake Commission) 

takes risk offshore 

• Risk reduction legislation 

• Strong civil defence agency and culture 

• Building codes on a par with California and Japan 

Short term 

• Immediate financial relief to SME’s and unemployed workers post Feb 22 nd 

• Recognition that rebuild in the worst of the liquefactiuon areas is not 

sustainable - government has, thus far, purchased > 7000 homes 

• Declared a state of national emergency following Feb 22 nd to enable 

full government support of response phase 

• Establishment of a government department – the Canterbury Earthquake 

Recovery Authority to manage the Recovery (5 year policy mandate in 

cooperation with local and regional authorities to oversee sustainable rebuild 



Development of an operational time-varying earthquake forecast 

(a GEM goal) 

• Used to inform update of building 

codes 

• Accounts for different earthquake 

clustering scales 

• Combines four different models 

• Used to estimate probabilities of 

ground shaking 

Increasing time scale 

• Short-term clustering model 

• Days to Year(s) 

• Medium-term clustering model 

• Years to decades 

• Long-term average model 

• Average earthquake rate since 

1960 

• NSHM fault model 

• Longest-term mostly timeindependent 



Refined Forecast for Canterbury region (whole of Canterbury Plains) 

star;ng April 15th, 2012 

1 Month 1 Year 

Prob 

Prob 

5.0-5.4 15% 76% 

5.5-5.9 5% 34% 

6.0-6.4 1% 11% 

6.5-6.9

Revised Forecast for Canterbury region star;ng July 1 st , 2012 

Revised Model. All forecasts start July 1 st , 2012 and use all data up to 

Jan 25 th , 2012. These forecasts use the “50-‐year” model. 



Revised understanding of performance requirements 

1 

PGAs for Liquefaction Assessment -‐ Mmin 5.0 and 5.5 

0.1 

Onset of damaging 

liquefaction 

Mmin5 .0 SLS=0.13g 

Mmin 5.5 SLS=0.10g 

Worst case SLS=0.165g 

Annual Exceedance Rate 

0.01 

1/25 Annual Exceedance Rate 

1/500 Annual Exceedance Rate 

Mmin=5.00, Max=8.0, Sdratio=1.5 

Weighted combination Mmin=5.5 

Weighted combination Mmin=5.0 

0.001 

Solid black weighted combination Mmin=5.5 

(including Bradley) 

Solid blue weighted combination Mmin=5.0 

Dashed blue max individual curve Mmin=5.0 

0.0001 

0.01 0.1 1 

Deep/Soft Soil PGA (g) 

• Liquefaction mitigation must be 

part of the rebuild – red zone + 

enhanced foundations 

• Structural design for life safety 

well understood, but low damage 

design & serviceability needs 

more work 

• Resilient infrastructure rebuild 

well underway 



Major lessons emerging 

1. Land use planning controls to limit exposure to known liquefaction 

susceptibility were not enacted – failure to deflect development pressure 

and failure by science to spell-out likely impacts or consequences. 

2. Failure to find a solution to known earthquake prone building risk – 

this is largely a URM and older concrete inventory, not the 

two multistory buildings that collapsed. The built environment 

generally performed as expected or better than expected under 

extreme ground motions. 

3. Poor communication of what building codes and rapid building 

inspections mean, and in risk communication. Engineers and scientists 

should talk to the public in terms of in observed damage, not “safe”, and 

in terms of consequences or impacts, not earthquake magnitudes and 

frequencies. 



Canterbury earthquakes as a case-study for GEM 

• In a small country with fairly well integrated policy function and a modest sized 

sequence of events in a modest sized city, data are available for all aspects of 

hazard, risk, and socio-economic impacts. 

• There is a very rich dataset to assess the fragility of the built environment and 

society that is transferable to most western countries. 

• The building stock in Canterbury has been exposed to a series of design level 

events which is beyond (globally) most (all) code expectations. Data on progressive 

degradation of structural performance and serviceability characteristics have been 

recorded. 

• Liquefaction-induced damage has been a major component of residential and to 

some extent commercial losses. An excellent dataset to tune understanding of 

vulnerability of the built environment to liquefaction (above and below ground), 

across a range of soil types is available. 

• Small government means there is an archive of policy decisions extending through 

response and recovery across all sectors, and policy in building future resilience. 



Rebuilding – impediments and opportunities 

Balance between optimism and pessimism 

• Building standards (life risk + serviceability) 

• Insurability 

• Investment capital 

• Technical considerations (short term EQ risk, liquefaction) 

• The biggest build NZ will ever do (we hope) – a major urban renewal 

project

Hard lessons for hazard, risk and socio-economic impacts of the ...

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