The Sliding Surface and Volume Seismicity of Qazvin Plain in West Tehran, with Special Reference to the Buin-Zahra Earthquake of 1962 and Changureh (Avaj) Earthquake of 2002

On the occasion of the 50th anniversary of the Buin-Zahra Earthquake of 1 September 1962, a case study on the seismicity of Qazvin plain in west Tehran area was performed, from which the results are presented herein. The methodology of the study is based on the field observation on the archeological sites and the macroseismic epicenters of the 20th century events in this region. In this article, it is tried to summarize the seismotectonic specifications of the Qazvin plain with an emphasis on the Buin-Zahra (1962) and Changureh (2002) earthquakes surface features. The probability of chain earthquakes in the western Tehran area is studied as well. The Estehard fault is located in the eastern end of the Ipak fault and the north Tehran fault is located in the eastern end of Eshtehard fault. This is important due to a seismic gap which exists in the western Tehran region. The population of Tehran and Karaj (in west Tehran) is an important factor due to seismic risk study in this active region.