Seismic vulnerability of low-rise residential buildings based on damage data from three earthquakes (Mw6.5, 6.5 and 6.3)

• The three earthquakes occurred in the same region and affected the same building typologies.
• In total 9500 buildings were included in the study, both damaged and undamaged.
• No buildings collapsed and there were no loss of life.
• Non-structural damage dominated the overall damage in all cases.
• Most of the damage occurred at 0–10 km distance from the fault rupture in the three events.

In June 2000 two Mw6.5 earthquakes occurred in South Iceland and in May 2008 an Mw6.3 quake struck 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 Mw6.5 events was considerably greater than in the Mw6.3 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.