ريزپهنه بندي لرزه اي شهر شيراز

Seismic micrzonation of shiraz

This paper presents some of the results of the seismic micro-zonation study of Shiraz city. Seismo-techtonics of the Shiraz region is studied. Strong motion parameters are calculated for Shiraz city and finally the characteristics of the surface soil layers are investigated by means of mi-crotremor measurements. In general the results showed that thick coarse deposits from the northwest areas gradually changes to fine deposits in southeast of the city. Seismic hazard analysis showed that the peak horizontal acceleration at the seismic bedrock level decreases from southwest to the northwest areas in Shiraz plane. Looking at a east-west cross-section rnicrotremor data indicated that the natural period of the surface soil deposits throughout the city is higher for the central part comparing to the east and west areas. This may suggest that the thickness of the deposits in this area is either larger than other zones or the deposits are softer. Moreover the natural period increases from northwest to southeast direction that could be due to thickening of the finer deposits in southeast areas.