Learning from recent destructive earthquakes in Iceland

In June 2000 two Mw6.5 earthquakes occurred in the middle of the largest agricultural region in Iceland and in May 2008 the region was hit again by a Mw6.3 event. The maximum inter-epicentral distance between these quakes was 38 km. The geology in Iceland is young and quite special and there are sites where stiff lava overlays sediments or soft sediment layers are sandwiched between lava layers. Strong motion data were recorded at a number of stations in the 2000 and 2008 events and valuable information about ground motion attenuation and site amplification were obtained. Furthermore, in each case nearly 5000 residential buildings were affected. A great deal of damage occurred but no residential buildings collapsed and there were no fatalities. Insurance against natural disasters is compulsory for all buildings and all properties are registered in a comprehensive inventory database. Therefore, to fulfil insurance claims, a field survey was carried out and a complete building-by-building loss database was established after the 2000 events and the 2008 quake which is international unique. Based on the loss databases seismic vulnerability models have been developed. The loss data and the models show that the overall seismic performance of the Icelandic buildings was outstanding. Timber buildings behaved best, then the RC buildings, whilst the masonry buildings were most vulnerable.