利用重复地震观测重庆武隆地区地壳介质变化  

Monitoring variation of crustal media in Wulong area of Chongqing Municipality by using repeating earthquakes

作　　者：汪建 杨亚运 马伟 Wang Jian;Yang Yayun;Ma Wei(Chongqing Earthquake Agency,Chongqing 401147,China)

机构地区：[1]重庆市地震局,重庆401147

出　　处：《地震科学进展》2021年第11期498-504,共7页Progress in Earthquake Sciences

基　　金：中国地震局监测、预报、科研三结合项目(3JH-2021040);重庆市地震局科研项目联合资助。

摘　　要：选取重庆数字地震台网记录的武隆地区107次M_(L)≥1.5地震波形和观测报告资料,采用波形互相关技术进行相关计算,识别出12组同时被3个地震台站记录且各台波形互相关系数不小于0.8的重复地震。利用射线追踪方法,对武隆地区重复地震位置做归一化处理,得到所选台站记录地震P波走时差变化,结果显示:在2017年武隆M_(S)5.0地震前4年,武隆、仙女山、涪陵地震台记录到P波走时差均存在长期的负异常变化,持续时间长达339天,共出现18次负值,表明该时段地壳介质速度有明显升高现象。The waveform and observation report data of 107 earthquakes with M_(L)≥1.5 recorded by Chongqing Digital Seismic Network in Wulong area were selected.The waveform cross-correlation technology was used for correlation calculation.12 groups of repeating earthquakes with waveform correlation coefficient larger than 0.8 and recorded by 3 seismic stations at the same time were identified.The position of repeating earthquakes in Wulong area was normalized by ray tracing method,and the change of P-wave travel-time difference of the selected stations was obtained.The results show that four years before the 2017 Wulong M_(S)5.0 earthquake,there are long-term negative abnormal changes in P-wave travel-time difference recorded by Wulong,Xiannushan and Fuling seismic stations,lasting for 339 days,with a total of 18 negative values.It shows that the crustal medium velocity increases obviously in this period.

关 键 词：重复地震 射线追踪 P波走时差 武隆地区 

分 类 号：P315[天文地球—地震学]