Seismic Microzonation of Tehran based on deterministic seismic hazard analysis and seismic indexes around faults

Abstract

Tehran has situated over several active faults such as Mosha, North Tehran, North Ray and South Ray faults and has experienced strong earthquakes in its history. It is possible the same earthquake occurs and result to large damages and many casualties. In this paper, seismic hazard analysis of Tehran city has been done with deterministic seismic hazard analysis, using specification of Tehran scenario active faults, soil conditions, average shear wave velocity extracted from several researches on Tehran area. To do this, a credible attenuation relation which considers effects of near source that has appropriate adaptation with Iran records has been used. In the following, deterministic seismic hazard analysis considering earthquake at closest distance to each mesh was done. Then, seismic output such as PGA, PGV, PGD and SA for all meshes of Tehran and their soil condition was done for each fault scenario. Then, maximum of seismic index was calculated for each and all scenarios on GIS and the results were evaluated. One of the main results of this article is calculation of seismic indexes near faults, so spectral acceleration near to North Tehran or Ray Faults with soil types I, II and III predicted as 1.2, 1.5 and 2g corresponding to predominant period of short buildings and it means high damages on areas over or near faults.

Keywords

• deterministic seismic hazrad analysis
• pga
• pgv
• pgd
• spectral acceleration