2015年12月7日塔吉克斯坦M_(S)7.4地震对远场小震活动的动态应力触发

DYNAMICALLY TRIGGERED FAR-FIELD MICROEARTHQUAKES FOLLOWING TAJIKISTAN M_(S)7.4 EARTHQUAKE ON DECEMBER 7,2015

采用离散波数法计算2015年12月7日塔吉克斯坦M_(S)7.4地震远场产生的库仑破裂应力变化,并结合β统计值检验方法,分析该地震对远场区域地震活动的应力触发作用。结果表明,①塔吉克斯坦M_(S)7.4地震在新疆库车、巴楚和喀什-乌恰地区的远场接收点产生动态应力变化为正,变化峰值分别为1.31 MPa、0.14 MPa和0.5 MPa,对库车和喀什-乌恰地区小震活动具有动态触发作用,与此相关,β统计值结果显示,塔吉克斯坦M_(S)7.4地震后库车地区地震活动性发生了较明显的改变,这与库车地区接收点库仑应力变化大小一致。②塔吉克斯坦M_(S)7.4地震在2016年11月25日阿克陶M_(S)6.7地震震中位置造成的最大动态库仑应力变化为1.0 MPa,表明阿克陶M_(S)6.7地震可能受到了塔吉克斯坦M_(S)7.4地震的应力触发作用,动态触发作用更为明显。

Based on the discrete-wave number method,we calculated the complete Coulomb failure stress(CFS)changes of far field region induced by December 7,2015 Tajikistan M_(S)7.4 earthquake,and theβstatistical value test method is used to analyze the stress triggering effect of strong earthquakes on the seismic activity in the fiar field.We find that the peak values of dynamic stress change in the remote Kuche,Bachu and Kashi-Wuqia areas are 1.31 MPa,0.14 MPa and 0.5 MPa,respectively,which have dynamic triggering effect on the microearthquake activities in Kuche and Kashi-Wuqia regions.The results ofβstatistical value show that,after the M_(S)7.4 earthquake in Tajikistan,the seismicity of Kuche area changed obviously.The maximum dynamic Coulomb stress change caused by the Tajikistan M_(S)7.4 earthquake at the epicenter of the Akto M_(S)6.7 earthquake on November 25,2016 was 1.0 MPa,indicating that the Akto M_(S)6.7 earthquake was affected by Tajikistan M_(S)7.4 earthquake.Dynamic triggering effect is more obvious.This is consistent with the aforementioned M_(S)7.4 of Tajikistans promotion of seismic activity in the Kashi-Wuqia confluence area.