Near-field Ground Motion Simulation for Heterogeneous Faulting

Category Tectonic & Seismotectonic
Group GSI.IR
Location 4th internetional Conference on Seismology
Holding Date 11 March 2008
     In engineering practice, the fault main parameters such as slip time function, effective stress, stress drop etc, are assumed to be constant on the fault plane. This assumption may be valid for simulation of long period ground motion in far-field observations. However, recent studies concerning the generation of highfrequency seismic waves using near-field observations indicate that the source function is complex, which is due to heterogeneities in the distributions of the strength or stress drop on the fault plane. The excitation and propagation of highfrequency seismic waves play an important role in aseismic design of building structures and are of special interest in earthquake engineering. Therefore, it is an important task to investigate the variability of the slip distribution on the fault plane and its effect on near-field ground motion.
Here, the characteristics of near-field ground motion in different directions are investigated taking into account slip heterogeneity on the fault plane. To this end, the near-field motions are synthesized using theoretical Green's function for different size of asperities on the fault. Based on simulated results, the effect of asperity growth on near-field motions is investigated and discussed. Furthermore, the variation of response spectrum with the asperity growth on the fault is also examined.

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