quake/ss nz-quake-10.ss_full.jpg Christchurch cathedral Magnitude SOUTH ISLAND OF NEW ZEALAND

quake/ss nz-quake-10.ss_full.jpg Christchurch cathedral Reasons for high levels of loss: 1)Location of the earthquake 2)Peak ground accelerations 3)Nature of the buildings 4)Ground conditions 5)Time of day 3/on-the-causes-of-the-high-levels-of- loss-in-the-christchurch-earthquake/

Canterbury M7.2 earthquake Sept M6.3 aftershock Feb. 21, 2011 All aftershocks since Sept (red are deep; star is Feb 21, 2011 event)

Shaking intensity in the city was much greater for this earthquake than the magnitude 7.1 earthquake from last September, or any of the aftershocks. The highest shaking was recorded at Pages Road Pumping Station at 188 %g, with readings of 127 %g at Heathcote Valley Primary School and 107 %g at Hulverstone Road Pumping Station. This is due to the proximity of the epicentre to the city and the shallow depth. The earthquake has a reverse faulting mechanism. badly-damaged-by-magnitude-6-3-earthquake.html

Nature of the buildings: good earthquake building safety regulation, but old ones are hard to retrofit and this was very strong shaking even for newish buildings

Ground conditions and liquefaction

Time of day: people are out and about at 11 am

Important implications for the effects of M6 earthquakes in places like the US mid continent where some think that there would be only modest damage from such events.