SEISMIC VELOCITY AND DISPLACEMENT HAZARD ASSESSMENT FOR TEHRAN, INCLUDING SITE EFFECTS

Estimation of earthquake parameters using probabilistic method has become very common in recent years. In Iran and especially for Tehran several studies have been performed to analyze the seismic hazard. Regarding the rapid development of lifeline facilities and the construction of few tall buildings in Tehran as well as the good correlation that exists between Peak Ground Velocity (PGV) and Peak Ground Displacement (PGD) with seismic behavior of such structures, seismic velocity and displacement hazard analyses for the region can be very useful. In this study probabilistic seismic hazard analyses of PGV and PGD, for a network of 31×31 points within Tehran are conducted. For each element incorporated in analysis (e.g. seismicity parameters, attenuation relationships, etc.) various alternatives are employed. Results of hazard analysis using any combination of these alternatives are obtained using SEISRISK III program, for 4 hazard levels including site effects and combined subsequently using logic-tree approach. According to the results, for the probability of exceedence of 2, 10, 20 and 50 percent in 50 years, the maximum values of PGV are 105, 51.5, 35.4 and 18.7 cm/s, respectively. For the aforementioned hazard levels, the corresponding PGDs are 56, 20, 11.7 and 4.5 cm, respectively.