苍山地震库仑破裂应力变化与地震活动相关性探讨

Effects of Coulomb Stress Changes from the 1995 Cangshan M5.2 Earthquake

本文收集了苍山地震周围断层的几何参数和运动学参数,选择不同的接受断层,研究了苍山地震库仑应力变化对余震及周边断层活动的影响。结果表明,苍山地震正的库仑应力变化对余震活动有促进作用,大部分苍山余震分布于库仑应力变化增加区域,应力增加量值为0.003～0.005MPa。通过对比该地区苍山地震前后16年的地震资料,发现苍山地震正的库仑应力变化对苍山断裂附近地震活动增强亦有一定的促进作用,而对于周边其他断层,由于距离较远,库仑应力变化量较小,苍山地震库仑应力变化的影响可以忽略。

In order to investigate Coulomb stress changes from the 1995 Cangshan M5.2 earthquake and the effects on surrounding faults,geometry parameters and kinematic parameters of faults have been collected and different received faults are used.The results show that the positive Coulomb stress promotes aftershock activities and most aftershocks distributed in Coulomb stress increasing region,the value of which is about 0.003~0.005 MPa.Comparing the seismic references of 16 years before and after the Cangshan earthquake,we found that positive Coulomb stress increases the stress around Cangshan fault,but the effects of the Coulomb stress changes on other faults can be ignored due to the farther distance.