Seismotectonic and seismic hazard analysis in Dezful and Susa cities

This research focuses on seismotectonic setting and seismic risk analysis of Dezful and Susa cities for 50 km radius. It helps to the safety of critical structures, and optimum siting of new projects in these cities. Results of the study lead to protect lives and decrease economic risks when a probable earthquake will occur in the area. For these purposes, geological investigations, and recognition of faults, as well as their geometry in this region carried out. Moreover, the seismic background of these cities evaluated. The ground motion parameters estimate by probabilistic seismic hazard analysis in defferent probability. For return periods of 25, 50, 100, and 200 years, results show that the maximum magnitude of design base earthquake (DBE) is 5.4, 5.6, 5.9, 6.1 Richter, respectively. For Dezful city, the maximum acceleration of design base earthquake and maximum credible earthquake calculate 0.22 and 0.33g, respectively, using Donovan equation. In addition, these parameters, for Susa city, estimate equal to 0.24 and 0.36g. The seismic zonation maps revealed that the highest risk of the area located in middle and northern parts. Therefore, it is necessary to retrofit the historical and worn-out urban structures.