Site specific probabilistic seismic hazard model for Isfahan, Iran: estimates and uncertainties

Abstract

We present a seismic source characterization model for the probabilistic seismic hazard assessment (PSHA) of the Isfahan urban area, Iran. We compiled the required datasets including the earthquake catalogue and the geological and seismotectonic structure and faults systems within the study region to delineate and characterize seismic source models. We identi ed seven relatively large zones that bound each region with similar seismotectonic characteristics and catalogue completeness periods. These regions were used for calculating the b-value of the Gutenberg-Richter magnitude recurrence relationship and for estimating the maximum magnitude value within each region. The recurrence parameters were then used to build a spatially varying distributed seismic source model using a smoothed kernel. Additionally, based on a fault database developed in this study and on a local expert's opinion about their slip velocity, an active faults based model is also created. We further performed sets of sensitivity analyses to nd stable estimates of the ground motion intensity and to de ne alternative branches for both the seismogenic source and ground motion prediction models. Site ampli cation is considered based on a Vs 30 map for