Probabilistic seismic hazard assessment for Lake Van basin, Turkey

The seismic hazard for the Lake Van basin is computed using a probabilistic approach, along with the earthquake data from 1907 to present. The spatial distribution of seismic events between the longitudes of 41–45° and the latitudes of 37.5–40°, which encompasses the region, indicates distinct seismic zones. The positions of these zones are well aligned with the known tectonic features such as the Tutak-Çaldıran fault zone, the Özalp fault zone, the Gevaş fault zone, the Bitlis fault zone and Karlıova junction where the North Anatolian fault zone and East Anatolian fault zone meet. These faults are known to have generated major earthquakes which strongly affected cities and towns such as Van, Muş, Bitlis, Özalp, Muradiye, Çaldıran, Erciş, Adilcevaz, Ahlat, Tatvan, Gevaş and Gürpınar. The recurrence intervals of Ms ≥ 4 earthquakes were evaluated in order to obtain the parameters of the Gutenberg–Richter measurements for seismic zones. More importantly, iso-acceleration maps of the basin were produced with a grid interval of 0.05 degrees. These maps are developed for 100- and 475- year return periods, utilizing the domestic attenuation relationships. A computer program called Sistehan II was utilized to generate these maps.