Seismic vulnerability of low-rise residential buildings based on damage data from three earthquakes (M_w6.5, 6.5 and 6.3)

In June 2000 two M_w6.5 earthquakes occurred in South Iceland and in May 2008 an M_w6struck in the same area. High PGAs (>0.6 g) were registered in all cases. The epicentres were located in an agriculture region and close to small towns and villages. Nearly 9500 residential buildings were affected. A great deal of damage occurred but there was no loss of life. Insurance against natural disasters is obligatory for all buildings in Iceland and they are all registered in a comprehensive property database. Therefore, after each quake a field survey was carried out where damage and repair costs were estimated for every structure. Most of the damage was observed in the near-fault area (0-10 km) but at longer distances it was significantly less. The damage in the two M_w6.5 events was considerably greater than in the M_w6.3 event. In all the events a high proportion of buildings were undamaged, even in the near-fault area. The main damage was non-structural, in interior walls and flooring. New buildings built after implementation of seismic codes performed better than those built pre-code.