An archeoseismology approach for identifying historical earthquakes in Sialk Kashan, Iran

Historical earthquakes play a notable role in engineering seismology. The historical Kashan-Sialk region, 3 Km south of Kashan, was surveyed in the viewpoint of historical earthquakes events. Several devastating historical earthquakes, occurred in the BC time, identified based on archaeological studies and evidences gathered from field study. In this respect a variety of information, namely time of settlement evacuation due to a natural disaster, walls and roofs collapses, unusual positions of skeletons, cracks and fractures on bones and earth were investigated. Signs of destructions and archeoseismology evidences suggested that an earthquake, with a magnitude of about 7, completely destroyed the Sialk hill. Kashan fault was introduced as an active and causative fault for this event. Effective distance from source (mezoseismic radius of Ambraseys), was used for the events which no evidences were available for their estimation. An empirical magnitude-radius relation was calculated, using regression on Ambraseys historical earthquakes catalogue to assign minimum magnitude to historical seismic events. Finally, a seismicity catalogue for Sialk ancient region and the neighboring area was prepared.