Earthquake in an MEDC - Christchurch, New Zealand

Background

When: 22^nd February 2011 at 12:51pm

Where: Christchurch, east of South Island, New Zealand

Epicentre: 10km south east of Christchurch

Depth of focus: 5km

Magnitude: 6.3

Causes

Conservative (Indo-Australian moving north-east, Pacific plate moving south-west)

Triggered quake: fault unzipping from September 2010 Darfield quake 

Primary Hazards

Ground shaking 

Fissure: 15km long 

Secondary Hazards

10 aftershocks 

Liquefaction caused flooding 

Landslides

Seismic lensing 

Fires

Warning Signs

 Darfield quake: Sept 2010 not far from Christchurch

Aftershocks from Darfield quake

BUT didn’t know fault was there – no landscape features

Monitoring

Seismometers by GeoNet

Step Model predicted 25% chance of an earthquake 6 weeks prior 

Management of threat

Strict + well enforced building code: earthquake proof buildings

Education + regular drills

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