The ground motion simulation of Kangding Mw6.0,2014 by the stochastic finite-fault model

The Xianshuihe Fault Zone is one of the most active fault zones in Southwest China, consisting of left-lateral, steeply dipping (70 to 80°), northeast-striking, segmented strike-slip faults. The Xianshuihe Fault Zone and the Ganzi-Yushu Fault together constitute the boundary between the Sichuan-Yunnan and Bayan Har crustal blocks, and undergo left-lateral strike-slip motion under a north-northeast-oriented regional maximum horizontal compressive stress . There are more than eight strong earthquakes with magnitude greater than M_w6.0 occurred in the Xianshuihe Fault Zone since 1893.

The November 22, 2014, Kangding strike-slip earthquake (M_w 6.0) occurred on the Southern Section of the Xianshuihe Fault Zone. Its epicenter was at 101.69°E, 30.26°N, source mechanism strikes N33°E, dips 82°, and slipped at an angle of -9°. In this work, we simulated ground motions by the stochastic finite-fault model(SFFM), including peak ground acceleration, peak velocity, and acceleration time-histories caused by this earthquake.

The Xianshuihe Fault Zone is very active and poses significant hazard to communities in the area. Thus, it is vitally important to develop appropriate ground-motion hazard maps for engineering design and other mitigation for the area. Although PSHA has been used to develop ground-motion hazard maps in China, recent studies have shown that PSHA is scientifically flawed . Thus, the use of PSHA has led to earthquakes in China such as the 2008 Wenchuan and 2010 Yushu being disastrous.

As demonstrated in this paper, scenario-based seismic hazard analysis is based on observations and well-known seismological relationships such as fault rupture dimension and the magnitude relationship of Wells and Coppersmith. Thus, the results have a sound physics base and can be easily tested. For example, the scenario-based hazard map can be directly compared with historical and future earthquakes in the Xianshuihe Fault Zone. Another advantage of scenario-based hazard analysis is that it can provide ground-motion time histories, which are important for engineering analysis and other applications.