重庆地区重复地震识别及在数字地震台网定位评价中的应用

Recognition of repeating earthquakes in Chongqing Area and its application in location evaluation of digital seismic network

利用重庆数字地震台网2010年1月至2017年12月的地震波形资料和观测报告,选出5个研究区1 251个ML≥1.5地震进行波形互相关计算,识别出358对同时被2个地震台站记录且各台波形互相关系数(cc)不小于0.8的重复地震对,涉及342个地震事件,约占地震总数的27%。将筛选出的重复地震对用于定量判断地震目录中震相拾取误差及评估台网定位精度,结果显示:重庆数字地震台网的垂直定位误差约为3 km,水平定位误差约为5 km,Pg、Sg震相拾取误差分别为0.5 s和0.7 s;其中武隆区地震定位和震相拾取精度最高,綦江区最低。

Using seismic waveform data and observation reports of the Chongqing Digital Seismic Network from January 2010 to December 2017, 1 251 earthquakes with ML≥ 1.5 in five research areas were selected for waveform cross-correlation. 358 earthquake doublets with waveform correlation coefficient no less than 0.8 and recorded by 2 stations were recognized, involving 342 earthquakes, being 27% of the whole events. Seismic phase picking error and location accuracy are quantitatively evaluated using recognized earthquake doublets. Results show that the vertical location error of the Chongqing Digital Seismic Network is about 3 km, the horizontal location error is about 5 km, and the Pg and Sg phase picking errors are 0.5 s and 0.7 s respectively;among them, the accuracy of seismic location and phase picking in the Wulong area is the highest, while that in the Qijiang area is the lowest.