SEISMIC HAZARD ANALYSIS FOR HIGHWAY NETWORK BASED ON STOCHASTIC FINITE FAULT MODELING OF GROUND MOTIONS

To improve the shortcoming of the traditional point-source based probability seismic hazard analysis (PSHA), the stochastic finite-fault modeling approach, which involves source, propagation path, and local site, is used to simulate ground motions for a given highway network that covers several intensity regions in southwest China. Based on simulated motions, the ground motion prediction equations (GMPEs) for peak ground acceleration (PGA) and pseudo spectral acceleration (PSA) are obtained by regression. The GMPEs are then applied in PSHA to obtain the seismic hazard curves for the bridges of the highway network. The obtained hazard curve is compared to the hazard curve computed based on traditional GMPEs for various hazard level. The result shows that:for a frequent earthquake, the simulation-based hazard curve provides safer ground motion parameters than the record-based hazard curve; for a basic, rare, and very rare earthquake, the ground motion parameters from record-based hazard curve are more conservative; the difference of the parameters between two hazard curves shows an obvious directivity, which indicates that, by involving finite fault model, PSHA is strengthened to represent the effect of fault mechanism.