Scenario-Based Seismic Hazard Analysis for the Xianshuihe Fault Zone, Southwest China

The Xianshuihe fault zone consists of left-lateral, segmented strike-slip faults, which produce strong and relatively frequent earthquakes, and exposes millions of people to the risk of strong motion and earthquake-induced geologic hazards in Southwest China. Seismicity in this fault zone exhibits typical features of characteristic earthquakes. The stochastic finite-fault model was used to generate time-histories and peak values of strong ground motion at near-fault locations for the characteristic earthquakes. First, the source parameters were determined and verified by comparing them with the simulated time-histories and intensity distribution and observations from the 2014 Kangding earthquake (M (w) 6.0). Then, scenario-based ground-motion hazard maps were produced from simulated ground motions of characteristic earthquakes. The scenario-based ground-motion hazard maps can be directly compared with historical and future earthquakes in the Xianshuihe fault zone. Scenario-based seismic hazard analysis also has other advantages. Our results show that current design ground motion for the Xianshuihe Fault area is not adequate.