This study develops the seismic hazard maps for city of Tehran, the capital of Iran. The city is located in a seismically active region and a few historical catastrophic earthquakes have occurred around the region. According to a number of studies, there are several major fault systems in and around the city. In this study, the fault systems were considered as seismic sources, with their respective geographical boundaries and possible maximum earthquake magnitude being estimated from the literature. Accordingly, the seismic hazard maps were developed using a deterministic approach....[ Read more ]

This study develops the seismic hazard maps for city of Tehran, the capital of Iran. The city is located in a seismically active region and a few historical catastrophic earthquakes have occurred around the region. According to a number of studies, there are several major fault systems in and around the city. In this study, the fault systems were considered as seismic sources, with their respective geographical boundaries and possible maximum earthquake magnitude being estimated from the literature. Accordingly, the seismic hazard maps were developed using a deterministic approach.

Furthermore, the present study intends to develop a modified time-dependent approach based on DSHA, in which non-controlling seismic sources are considered. The modified DSHA (Semi-DSHA, or SDSHA) method is utilized in the Tehran city and hazard distribution maps with 10% and 2% probability of exceedance in 50 years are developed, respectively. In addition, the uniform hazard spectra resulting from SDSHA are used as target spectra in the ground motion selection process for site amplification analysis in the city.

The site amplification analysis is performed in the study area. For this purpose the equivalent linear approach is adopted. In this study the uncertainty of the soil profile parameters and input ground motions have been investigated. A Monte Carlo simulation with all parameters randomization has been conducted for a number of locations near the city center area of Tehran. Mean and mean plus one standard deviation surface response spectra resulting from the uncertainty of soil profile parameters have been computed and presented. The results show that the mean maximum amplification factor is as high as 3 and it follows the lognormal distribution. However, a set of detailed in-situ tests can be performed in the study area to calculate the mean values and ranges of variation of input parameters more precisely.