利用重复地震观测粤闽交界地区地壳介质变化

Monitoring crustal media variation in the border area between Guangdong and Fujian Provinces by using repeating earthquakes

摘要:

利用粤闽两省数字化地震台网2007年6月～2010年5月的走时及波形记录对南澳地区ML≥1地震用双差法重新进行定位,根据定位结果挑选重复地震丛,并研究地震丛的P波走时经伪弯曲射线追踪技术及波形互相关校正后的走时差变化。经上述处理后,汕头台、潮州台记录的南澳地区地震的P波走时差在2008年6～8月间出现负异常,经与地震活动性及形变观测资料对比分析,认为该时段的负异常反映了区域地壳介质速度有所上升。

Abstract:

In this paper，we relocated earthquakes sequences occurring in the border area between Guangdong and Fujian Provinces from June，2007 to May，2010 using the doubledifference location algorithm． During relocating，the cross correlation of waveform data and seismic wave travel time were used． The repeating earthquakes were selected according to the relocated result． We normalized the position of repeating earthquakes by using ray tracing． The accuracy of P-wave travel time can be improved by using ray tracing and cross correlation of waveform data，and the crustal media variation can be measured． According the calculation routine，P-wave travel time difference of the Shantou and Chaozhou seismic station retained negative anomaly from June to August，2008． After contrasting with seismic activity and crustal deformation of the Shantou and Chaozhou seismic station，we believe that the negative anomaly from June to August，2008 indicated the short-term velocity variation of crustal media．