利用震源机制判别山西地区地震事件类型

Using Focal Mechanism to Distinguish Types of Earthquake Events in Shanxi

采用gCAP方法反演2010~2019年山西地区87次天然地震、18次塌陷及9次爆破的全矩张量解。结果显示,gCAP方法在反演山西地区震源机制方面效果较好。2016-03-12山西盐湖M L4.8地震的断层错动方式为走滑兼正断,全矩张量解中包含非双力偶成分,属于体积缩小的内向闭合型破裂。对于山西地区的地震事件,可将全矩张量解中双力偶分量占比是否大于80%作为判别天然地震及非天然地震的依据。对于非天然地震事件,当参数ζ>0时为外向爆炸源,反之为内向闭合源。

Using the gCAP method,we determine several full moment tensor solutions of 87 natural earthquakes,18 collapse events and 9 blasting events that occurred from 2010 to 2019 in Shanxi.The results show that the gCAP method has a good effect in inverting the focal mechanism solution in Shanxi.The fault movement of Yanhu M L4.8 earthquake in Shanxi on March 12,2016 was strike-slip and normal fault,which is an inward closed fracture with reduced volume,having an obvious non-double-couple component.Whether the proportion of dual-couple components in the full moment tensor solution of earthquake events in Shanxi is greater than 80%can be used as a basis for distinguishing between natural earthquakes and non-natural earthquake events.For non-natural earthquake events,when the parameterζ>0,it is an outward explosion source,on the contrary,it is an inward closed source.