2014年四川康定MS6.3和MS5.8地震的应力触发研究

以2014年四川康定M_S6.3和M_S5.8地震为研究对象,计算了2次主震在近场和周围断层造成的库仑破裂应力变化,研究主震与余震的触发关系,以及2次主震对周围断层施加的应力负荷作用。结果表明:2次主震的共同作用控制了后续地震活动的演化趋势,其中康定M_S6.3地震产生的库仑破裂应力变化对后续余震事件的触发占主导作用。鲜水河断裂带南段和安宁河断裂带受到了一定的应力加载作用,未来地震活动的趋势可能会加强。

Study on Stress Triggering of 2014 Kangding MS6.3 and MS5.8 Earthquakes

In this study,the problem of earthquake triggering is discussed by using the M_S6.3 earthquake on Nov.22,2014 and the M_S5.8 earthquake on Nov.25,2014 in Kangding,Sichuan Province.Firstly,based on the regional tectonic stress field in this area,we calculated the spatial distributions of static stress changes caused by the Kangding M_S6.3 and M_S5.8 earthquakes on the optimal fault planes,and studied the stress triggering effect of the main shock to the aftershocks.Furthermore,we analyzed the stress loading and unloading effects of the two main-shocks on the surrounding faults by calculating the Coulomb rupture stress changes on the surrounding faults.The results show that the joint action of the two main earthquakes controls the evolution trend of the subsequent seismicity.Moreover,the Coulomb failure stress change produced by the Kangding M_S6.3 earthquake has a good correlation with the aftershocks,and the triggering effect on the subsequent events is dominant.In addition,the southern segment of the Xianshuihe fault and the Anninghe fault are subjected to certain stress loading by two earthquakes,and the seismic activity may be strengthened in the future.