Simulation of 2009, Mw=4 Tehran earthquake using a hybrid method of modal summation and finite difference

The Greater Tehran area is the most important city of Iran and hosts about 20% of the country population. Despite the presence of major faults and the occurrence of historical earthquakes, nowadays the seismicity is relatively quite low and this enhances the use of simulation methods for microzonation and seismic hazard assessment. To simulate the ground motion caused by the 2009, Mw 4 earthquake, occurred south-east of the city, a hybrid technique is used. It combines two methods: the analytical modal summation and the numerical finite difference, taking advantage of the merits of both. The modal summation is applied to simulate wave propagation from the source to the sedimentary basin and finite differences to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Time and frequency domain parameters are simulated along 2 (E-W and SE-NW) profiles for various stations.