九寨沟M_S7.0地震静态库仑应力触发及对附近断层影响分析

Analysis on the triggering of the Jiuzhaigou M_S7.0 earthquake's static Coulomb stress and its influences on its adjacent faults

计算和研究了1973~2013年巴颜喀拉块体东边界发生的6次M_S≥6.5地震引起的静态库仑应力变化图像,认为先前发生的6次地震对2017年8月8日九寨沟M_S7.0地震具有触发作用。九寨沟M_S7.0地震发生后,对震中附近主要断裂应力转移的计算结果显示,在巴颜喀拉块体东边界7次M_S≥6.5地震的共同作用下,东昆仑断裂带东段及龙日坝断裂带库仑应力水平升高,具有触发作用;岷江断裂带处于库仑应力影区内,具有减震效应。

In this paper,patterns of static Coulomb stress change induced by a sequence of 6 earthquakes with M_S≥6.5 occurring in the east boundary of the Bayan Har block from 1973 to2013 are calculated and studied,and the result suggests that the pre-earthquakes played a triggering role on the Jiuzhaigou M_S7.0 earthquake of August 8,2017. Further,we calculated the stress transference focused on the major faults near the Jiuzhaigou M_S7.0 earthquake epicenter co-induced by a sequence of 7 earthquakes with M_S≥6.5 in the east boundary of the Bayan Har block and the results show that both the eastern section of the East Kunlun Fault and the Longriba fault are in the stress triggering zone,while the Minjiang fault is in the stress shadow zone. Finally,we should pay more attention to the possibility of strong earthquake risk in the eastern section of the East Kunlun Fault zone in the near future due to the existence of the Maqu seismic gap along this section.