Stochastic finite-fault simulation for the 2002 Changureh-Avaj earthquake, NW Iran


1 Building and Housing Research Center, P.O. Box 13145-1696, Tehran, Iran

2 Institute of Geophysics, University of Tehran, P.O. Box 14155-6466, Tehran, Iran

3 International Institute of Earthquake Engineering and Seismology, Tehran, Iran


Stochastic finite-fault simulation is used to simulate the acceleration time histories of the 22 June 2002 Changoureh-Avaj earthquake. The method generalizes the stochastic ground motion simulation technique, developed for point source, to the case of finite faults, in which the ground motion amplitudes are simulated as a summation of stochastic point source. Geometrical spreading and regional inelastic attenuation are included in the model. The strong motion simulations are performed by adjusting the sub-fault size to calibrate the simulation model against recorded ground motions. In this way the length of the fault is taken as 25 km and its width as 18 km, and the fault plane is divided into 5×3 elements. Considering that site amplification functions play an important role in the simulation process, site specific amplification function is estimated by the horizontal to vertical ratio technique.
A quite satisfactory agreement is found between the simulated amplitude Fourier spectra and the recorded data at frequencies of engineering interest (0.1 to 20 Hz) including the capability of the method to reproduce the salient ground motion characteristics.