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A talk on tectonic hazards with reference to the earthquake sequence in Christchurch, New Zealand

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Plate Tectonics & associated hazards: Christchurch, New Zealand David Petley Dean of Research and Wilson Professor of Hazard and Risk Blog site: http://blogs.agu.org/landslideblog/ Twitter: @davepetley :

Plate Tectonics & associated hazards: Christchurch, New Zealand David Petley Dean of Research and Wilson Professor of Hazard and Risk Blog site: http ://blogs.agu.org/landslideblog / Twitter: @ davepetley Institute for Hazard, Risk and Resilience

Geological setting of New Zealand:

Geological setting of New Zealand GNS Science / Geonet

New Zealand tectonic setting:

New Zealand tectonic setting GNS Science / Geonet

PowerPoint Presentation:

Geology.com

PowerPoint Presentation:

NASA

PowerPoint Presentation:

NASA

PowerPoint Presentation:

2007 New Zealand Seismic Hazard Map 2% in 50 year probability of excedance

2007 New Zealand Seismic Hazard Map – Christchurch 2% in 50 year probability of excedance:

2007 New Zealand Seismic Hazard Map – Christchurch 2% in 50 year probability of excedance

Darfield earthquake:

Darfield earthquake 4 th September 2010 ML=7.1 Depth = 10 km Peak ground acceleration = 1.26 g GNS Science

PowerPoint Presentation:

GNS Science

Surface expression of the Darfield fault :

Surface expression of the Darfield fault Image: Malcolm Teesdale

Darfield earthquake fault trace:

Darfield earthquake fault trace

PowerPoint Presentation:

GNS Science

Impact:

Impact

Darfield earthquake losses:

Darfield earthquake losses No direct deaths (1 fatal heart attack) Two serious injuries Estimated losses: Total loss: US$6500m ($5000m‐$ 7876m) 4.8% of NZ GDP Insured loss : US$3900m ($3040m‐$5500m) EQC loss: $ 1150m, remainder covered by reinsurance 3 rd highest insured loss at that time http ://earthquake-report.com/wp-content/uploads/2011/03/CATDAT-EQ-Data-1st-Annual-Review-2010-James-Daniell-03-03-2011.pdf

Landslides and rockfalls:

Landslides and rockfalls

Darfield earthquake and aftershocks:

Darfield earthquake and aftershocks GNS Science

PowerPoint Presentation:

GNS Science

February 2011 earthquake:

February 2011 earthquake Aftershock of Darfield earthquake 12:51 on 22 nd Feb 2011 ML = 6.3 at 5 km depth 10 kilometres (6 mi) south-east of the centre of Christchurch 184 people killed

Geonet Peak Ground Acceleration map:

Geonet Peak Ground Acceleration map GNS Science

Liquefaction:

Liquefaction GNS Science

Why such high accelerations?:

Why such high accelerations? Proximity to the city Brittleness of fault materials (near instantaneous rupture) Direction of energy release Slapdown (trampoline) – vertical accelerations

Losses:

Losses 184 fatalities Including 115 in the CTV building 1500 – 2000 injuries Total loss: $16billion ($15 – 20 billion) Insured loss: $ 13 billion ($11 - $16.25 billion) About 13% of GDP 156,500 buildings damaged

Topography:

Topography

PowerPoint Presentation:

GNS Science

PowerPoint Presentation:

GNS Science

The June 2011 earthquake:

The June 2011 earthquake 13 th June at 14:20 local time ML = 6.3 Depth = 6.9 km Peak acceleration = 2.13 g, 0.78 g in the city centre Losses: 1 dead, 46 injured Costs – unclear, probably about $4.4 billion Triggered further building collapses and liquefaction Many rockfalls

PowerPoint Presentation:

GNS Science

Earthquake Commission – risk sharing:

Earthquake Commission – risk sharing

PowerPoint Presentation:

Conclusions: GNS Science

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