We have also learned that some earthquakes cannot be thought of as a short sharp event, but rather are a rolling set of shocks with a long period of continuing after-quakes. These can cause on-going damage, delay assessment, continue disruption, and slow reconstruction. The impact of ongoing seismic instability on insurance and construction can be very marked.
We have seen how earthquake damage is hugely sensitive to magnitude, depth, location and timing of day and week. In 2009 the biggest earthquake in the Southern Hemisphere occurred in Fiordland, 7.8 on the Richter Scale. It caused no damage at all.