sPL震相在海城地区震源深度测定中的应用  

The Application of the sPL Phase in Haicheng Area in Determination of Focal Depth

作　　者：杨士超 王亮[1] 孙庆山 焦明若[1] 钱蕊[1] YANG Shichao;WANG Liang;SUN Qingshan;JIAO Mingruo;QIAN Rui(Liaoning Earthquake Agency,44 North-Huanghe Street,Shenyang 110034,China)

机构地区：[1]辽宁省地震局,沈阳市110034

出　　处：《大地测量与地球动力学》2023年第5期523-528,共6页Journal of Geodesy and Geodynamics

基　　金：中国地震局地震科技星火计划(XH21008Y,XH23009YA);中国地震局震情跟踪定向工作任务(2022010117,2022010301);辽宁省地震局预研孵化课题(2022025)。

摘　　要：利用sPL深度震相对1999~2020年海城老震区M_(L)≥3.0地震震源深度进行重新测定,共识别出146次地震事件的sPL震相,其中sPL震相与P波到时差在1.2~3.2 s之间,震源深度在5~15 km范围内。研究发现,1999年岫岩MS5.4主震发生前地震序列的震源深度保持在8 km附近,与主震的震源深度相当;临近主震发生时,在5.5 km深度处出现破裂,随后震源深度从5.5 km开始变深,逐渐逼近主震震源深度,存在震源深度由浅及深的迁移过程;岫岩MS5.4主震发生后,震源深度破裂范围扩展,浅部依然有地震发生,更深的位置也发生地震。We use the sPL depth phase to remeasure the focal depth of M_(L)≥3.0 earthquakes in Haicheng old earthquake area from 1999 to 2020.We identify a total of 146 seismic events.The time difference between the sPL and P wave arrival is between 1.2 to 3.2 s,and the focal depth is in the range of 5 to 15 km.We find that the initial focal depth of the Xiuyan M S5.4 earthquake sequence in 1999 before the occurrence of the main shock was kept around 8 km,which is equivalent to the focal depth of the main earthquake.When the adjacent main shock occurred,the rupture occurred at 5.5 km,and then the focal depth deepened from 5.5 km,gradually approaching the focal depth of the main shock,and there was a migration process of focal depth from shallow to deep.After the Xiuyan M S5.4 main shock,the fracture range expanded,and there were earthquakes in the shallow as well as in the deeper part.

关 键 词：海城老震区 sPL震相 震源深度 地震迁移 

分 类 号：P315[天文地球—地震学] P313[天文地球—固体地球物理学]