Probabilistic seismic hazard analyses and obtaining uniform hazard spectra of Tabriz, Iran

In this study Probabilistic Seismic Hazard Analysis is carried out for Tabriz region and results are presented by spectral isoacceleration maps and Uniform Hazard Spectra (UHS) for two levels of hazard. To achieve this goal, at first a catalog of all the historical and instrumentally recorded earthquakes covering timeline from 858 up to 2010, in a radius of 200 km around Tabriz city, has been gathered and processed for elimination of the aftershocks and foreshocks from main occurrences list and then seismicity parameters have been obtained by Kijko (2000) method. The seismic sources of the considered region have been studied and modeled. Probabilistic seismic hazard analysis is implemented for 22*17 grid points over Tabriz region and it’s vicinity using SEISRISK III (1987) software by employing four attenuation relationships and two relationships between earthquake maximum magnitude and fault rupture length. The Results are combined using logic tree method and shown by spectral acceleration maps and Uniform Hazard Spectra with 2 and 10% probability of exceedence (PE) in 50 years for two types of soil.