Seismic vulnerability of icelandic residential buildings

The seismicity in Iceland is related to the Mid-Atlantic plate boundary which crosses the country from north to south. Since 1700, there have been 25 earthquakes of magnitude six or greater in the two major seismic zones in Iceland. For many of the historical earthquakes (older than 100 years), detailed written descriptions are available that describe the damage from farm to farm. For the most recent earthquakes, like the two south Iceland earthquakes of June 2000 and the south Iceland earthquake of May 2008, comprehensive building-by-building loss data exist. The loss data in these cases are split into a number of subcategories of structural and non structural damage. The building stock in south Iceland has changed significantly from 1700 to the present. For ages, vulnerable turf and stone houses dominated, but in the twentieth century, concrete buildings and timber buildings took over. Seismic codes were implemented in 1976 and have gradually improved the seismic capacity of present building stock. In this book chapter, an overview of the seismic performance of old and new Icelandic buildings is given. Observed and reported damage caused by three earthquake sequences and a single event are discussed; first, the damage caused by two earthquakes in August 1784 in south Iceland; then, by the 1896 earthquake sequence in south Iceland; then, the damage after a single event in 1934 in north Iceland; and finally, the loss data from the 2000 and 2008 earthquakes in south Iceland. The main focus is on the last three events for which most of the data exist.