A Preliminary Probabilistic Seismic Hazard Analysis for Iran

The present study aimed to develop a preliminary seismic hazard zoning map of Iran. The seismic source zones of Iran are determined first, based on a study on the seismic trends and the seismotectonic zones. The seismicity parameters and the activity rates in each of the source zones are determined as well. The seismic hazard zoning is performed using the attenuation laws established by the author for Iran. The author tried to determine the seismic source zones for the using the knowledge on the strong motions records (more than 6000 three component records by the September 2006), as well as the seismotectonic characteristics of different regions of Iran. The seismic hazard assessments in Iran performed using probabilistic approach. The probabilistic approach applies the statistical models for the probabilistic assessment of return period of different strong motion parameters. The assessment of values of input parameters (Mmax, distance to the seismic source and the site conditions) and the selection of the attenuation models to evaluate the seismic hazard parameters contains different amounts of uncertainties. The Mmax is estimated based on the maximum observed earthquake; assessment of maximum probable earthquake for a seismic source and application of the empirical relationships between the magnitude and fault-length and/or width. The distances to the seismic source are defined as the direct surface distance to the fault; distance to the seismogenic depth and focal distance to the source. The resulted maps are presented in this paper for the return period of 475 years (horizontal component).