Finite fault inversion and hybrid broadband simulation of strong-motion records from the May 28, 2004, Baladeh, Iran, earthquake (Mw = 6.2)

Abstract

Tehran, the capital of Iran, is widely recognized as one of the world's most earthquake-vulnerable cities. Since there are no recorded ground motions of large earthquakes in the Tehran area, for seismological and earthquake engineering purposes, simulated ground motions may be useful in understanding the earthquake characteristics. On the other hand, ground motion simulation validation is an important and necessary task toward establishing the efficacy of physics-based ground motion simulations for seismic hazard analysis and earthquake engineering applications. This article presents a validation of the hybrid broadband ground motion simulation methodology through simulation of Baladeh 2004 earthquake (Mw 6.2). This earthquake occurred On May 28, 2004, in the Baladeh region in the North of Iran. This earthquake is remarkable because it was the first instrumentally recorded large earthquake near Tehran. In this paper, for the first time, we obtain slip distribution on the fault plane by finite fault inversion based on the neuro-fuzzy finite-fault approach. Next a hybrid broadband simulation of ground motion recorded during the main shock of the Baladeh earthquake is done. Then a combination of the finite difference method (0.1–1.0 Hz) and the stochastic finite fault method (1.0–20.0 Hz) is used for quantifying ground motion values. The validity of the results is checked by some empirical GMPEs, a quantitative score of Anderson, 2004, and also model bias of Graves and Pitarka (2010).