ABSTRACT

We present the first probabilistic seismic hazard assessment (PSHA) specifically for the Shanxi rift system, north China, which has been defined as one of the areas of highest seismic hazard and risk in China in recent decades. We applied a Monte Carlo‐based approach to PSHA, based on so far the most complete earthquake catalog available, a detailed zonation considering both seismicity distribution and local tectonic features, a logic tree of carefully selected ground‐motion prediction equations, as well as a cautious consideration of actual local site effects for this region. Both areal sources (for Ms<6.0) and fault sources (for Ms6.0) were considered, and a synthetic earthquake catalog was generated through Monte Carlo simulation. A logic tree was applied to represent the epistemic uncertainty related to attenuation models for the rift system. Actual local site effects were incorporated and the stability of the results was also tested in this study. Our results show that nearly the entire rift system faces a significant seismic hazard and associated high seismic risk, as more than 80% of the population and the main economical infrastructure of Shanxi are concentrated here. The highest hazard is found in the areas around the north margin of Tianzhen fault and the north segment of Hengshan fault in the north, and in the Linfen basin and the area around Zhongtiaoshan fault in the south of the rift system. Our results are comparable to, but a refinement of, the results of previous probabilistic seismic hazard studies in the region. Deaggregation of seismic hazard for five large cities in the rift system indicates that the seismic hazard is most contributed by the nearby sources. Results obtained in this study provide a better understanding of the seismic hazard in the Shanxi rift system and can thereby help guiding earthquake risk mitigation in the future.

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