2014年金寨M_L(3.9)震群序列遗漏地震检测及发震构造分析  

Missed Earthquake Detection and Seismogenic Structure Analysis of the Jinzhai M_(L)3.9 Earthquake Swarm Sequence in 2014

作　　者：倪红玉[1,2] 谭毅培 邓莉[3] 汪小厉[1,2] 鲍子文 方震 洪德全[1,2] Ni Hongyu;Tan Yipei;Deng Li;Wang Xiaoli;Bao Ziwen;Fang Zhen;Hong Dequan(Anhui Earthquake Agency,Hefei 230031,China;Mengcheng National Geophysical Observatory,Mengcheng 233500,Anhui,China;Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of CEA,Tianjin Earthquake Agency,Tianjin 300201,China)

机构地区：[1]安徽省地震局,合肥230031 [2]安徽蒙城地球物理国家野外科学观测研究站,安徽蒙城233500 [3]天津市地震局,中国地震局地震工程综合模拟与韧性抗震重点实验室,天津300201

出　　处：《中国地震》2021年第2期379-389,共11页Earthquake Research in China

基　　金：中国地震局地震科技星火计划(XH20026);2020年安徽省地震科研基金(20200501)共同资助。

摘　　要：针对2014年8月—2015年1月安徽金寨发生的M_(L)3.9震群,利用匹配滤波技术补充台网目录遗漏的地震事件,再利用波形互相关震相检测技术标定P波和S波到时,进一步采用双差定位方法对震群进行重定位,结合震源机制解等分析此次震群活动可能的发震构造。计算结果显示,通过互相关扫描检测到1376个地震台网常规分析遗漏的地震,数量约为台网目录给出的585个事件的2.35倍。检测到的遗漏地震震级估算为M_(L)0~2.3,通过震级-频次统计分析,加入遗漏地震后地震目录的完整性在M_(L)0~1.5范围内有较明显的改善。重定位后地震走时残差更小,水平位置更集中,沿NNE向断裂F和NW向青山-晓天断裂呈现近直立的条带状分布。结合地质构造、震源机制解和水库因素,推测2014年金寨M_(L)3.9震群可能是由周边水库水下渗引起NW向青山-晓天断裂与NNE向断裂F慢滑动而触发的。We herein used matched filter technique to supplement missing earthquakes from seismic network catalogue in Anhui Jinzhai M_(L)3.9 earthquake swarm occurred during August 2014 to January 2015,then we determined P and S wave arrival times using seismic phase detection technology based on waveform cross correlation method,and further used the double-difference location method to reposition the earthquake swarm.Combined with the source mechanism solution,the possible seismogenic structure was analyzed.The results show that 1376 missing earthquakes are detected by cross-correlation scanning,which is about 2.35 times of the 585 events given in seismic network catalogue.The magnitude of detected events is from M_(L)0 to M_(L)2.3.By magnitude-frequency analysis the catalog completeness is obviously improved in the range M_(L)0 to M L1.5.The relocation result of the newly detected and catalogue listed events shows that the RMS of travel times becomes smaller,the horizontal position becomes more concentrated,showing a nearly erect strip distribution along the NNE-trending fault F and the NW-trending fault Qingshan-Xiaotian.We suggest that the 2014 Jinzhai M_(L)3.9 earthquake swarm may be triggered by the slow sliding on both fault F and the fault Qingshan-Xiaotian which caused by the infiltration of the surrounding reservoir water.

关 键 词：匹配滤波 金寨震群 遗漏地震检测 双差定位 发震构造 

分 类 号：P315[天文地球—地震学]