云南双震型地震序列震源参数特征研究*

(云南省地震局,云南 昆明 650224)

双震型地震; 震源参数; 应力降; 障碍体; 地震预测

Study on Characteristics of Source Parameters of Double Shock Earthquake Sequence in Yunnan
YE Jian-qing,LI Yong,DUAN Yi,JIANG Fei-rui

(Earthquake Administration of Yunnan Province,Kunming 650024,Yunnan,China)

double shock earthquake; source parameter; stress drop; obstacle; earthquake prediction

备注

采用云南区域测震台网资料,运用布伦模式方法测算云南地区震源参数,对盐津、腾冲和川滇交界地区3个典型的双震型地震序列震源参数进行了综合分析研究。结果 表明双震型地震震源参数中,首次强震的应力降较低,可能是受震源区存在障碍体的影响,构造应力未能在首次地震中得以完整释放,再次发震其应力降值较高,表明已突破障碍体。从地震预测角度,首次地震的应力降大小,可以初步判定震区未来是否可能再次发震。

Basing on the data in Yunnan Regional Seismic Network,we calculated the source parameters of 2 533 3.0≤M(L,S)≤6.6 earthquakes in Yunnan from 1999 to 2013 by Brune circle model method,and analyzed the source parameters of three typical double shock earthquake sequence in the junction area of Yanjin,Tengchong and Yunnan-Sichuan. The result shows that in the source parameter of double shock earthquakes,the stress drop of the first shock is lower,which indicate the tectonic stress cannot be fully released by the effects of the existence of obstacle in focal region,however,the stress drop of the second shock is much higher than the first one,which indicate the obstacle has been broken through. In the aspect of earthquake prediction,the scaling of stress drop of the first shock can be used to make a preliminary determination whether the earthquake would happen again in focal region.