基于钻孔应变地震波记录确定地震面波应变震级  

Determination of seismic surface wave strain magnitude based on borehole strain seismic wave records

作　　者：李富珍 张怀 唐磊 石耀霖 LI FuZhen;ZHANG Huai;TANG Lei;SHI YaoLin(Key Laboratory of Computational Geodynamics,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;National Institute of Natural Hazards,Ministry of Emergency Management of the People′s Republic of China,Beijing 100085,China)

机构地区：[1]中国科学院大学地球与行星科学学院,计算地球动力学重点实验室,北京100049 [2]应急管理部国家自然灾害防治研究院,北京100085

出　　处：《地球物理学报》2021年第5期1620-1631,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金(U1839207,41590865,41774106,41974018);国家重点研发计划(2018YFC1504200);中央级公益性科研院所基本科研业务专项(ZDJ2018-09)共同资助.

摘　　要：近年发展的高采样率的钻孔应变仪可以记录到地震波造成的水平应变,是动态库仑应力研究的重要手段.利用钻孔应变仪记录的应变地震波确定地震震级,是一个重要的科学课题.本文收集了我国10个应变台站四分量钻孔应变仪2020年1—3月记录的10 Hz采样应变地震波资料,共选出震级M≥4.0的浅源地震68个,用最小二乘法求得应变震级公式为Mε=lg E max+1.65 lg(Δ)+1.43.对于6.5级以下的地震,计算得到的应变震级ε与中国地震台网中心公布的震级M CENC基本一致:M CENC=1.03ε-0.23,但本研究中的两个7级地震,应变震级出现了震级饱和现象.本文的基本结论是:应变定震级是可行的,但对于两个7级地震的饱和现象需要进一步深入研究,因为它们不但涉及震级确定,而且涉及远震动态库仑应力触发地震的研究.今后要对更多的大震钻孔应变波形记录进行分析.The high sampling rate borehole strain gauge,developed in recent years,can record the horizontal strain caused by seismic waves,which is a crucial method for the study of dynamic Coulomb stress.It is an important scientific topic to determine earthquake magnitude by using strain seismic waves that recorded by borehole strain gauge.In this study,strain seismic wave data recorded by four-component borehole strain gauges at ten stations in China from January to March in 2020 are collected,and a total of 68 shallow source earthquakes with magnitude M≥4.0 are selected.The strain magnitude formula obtained by using the least square method is Mε=lg E max+1.65 lg(Δ)+1.43.For earthquakes with magnitude M<6.5,the strain magnitudeεcalculated is basically consistent with the magnitude M CENC published by the China Earthquake Networks Center:M CENC=1.03ε-0.23.However,the strain magnitudes of the two earthquakes with magnitude M>7.0 in this study occur magnitude saturation phenomenon.The basic conclusion of this paper is that using strain to determine magnitude is basically feasible,but the saturation phenomenon of the two earthquakes with magnitude M>7.0 needs to be further studied.Because they contain not only the determination of earthquake magnitude,but also the study of triggering effect of dynamic Coulomb stress caused by remote earthquakes.In the future study,analyzing more borehole strain seismic wave records of large earthquakes are needed.

关 键 词：四分量钻孔应变仪 应变震级 震级测定 震级偏差 

分 类 号：P315[天文地球—地震学]