Simulation of probable scenarios ofearthquake occurrences in Tehran

Tehran metropolitan with a high population, existence of active faults, evidence of historical earthquakes and vulnerability of its infrastructures is exposed to a high seismic risk. In the present study, considering geological reports and papers published in the past decade, three scenario earthquakes for rupture of Mosha, Niavaran and Parchin faults are presented, and synthetic accelerograms were simulated in the Tehran metropolitan. Stochastic point source method with modification of distance parameter for considering finite fault effects is adopted; and results of studies carried out by International Institute of Earthquake Engineering and Seismology (IIEES) in the recent years have been considered to account for site effects. Simulation results show considerable PGA values for Niavaran fault rupture in northern Tehran and for Parchin fault rupture in southern Tehran; also average Modified Mercali Intensity (MMI) for these scenarios are equal to IX for districts 3 and 1 in Tehran, which indicates high damage potential in those areas. Using the simulation results, we have also carried out a preliminary estimation of casualty based on the assumed scenario earthquakes. Casualty (death toll) for rupture scenarios of Mosha, Niavaran and Parchin faults are estimated to be about 5000, 117000 and 85000, respectively.