2019年6月17日长宁M_(S)6.0地震前后地壳振动异常分析  

Anomalies of Ground Vibrations before and after the June 17,2019 Sichuan Changing M_(S)6.0 Earthquake

作　　者：于晨 王淑艳 陈界宏 杨志高[1] 李美[1] 余怀忠[1,4] Yu Chen;Wang Shuyan;Chen Chieh-Hung;Yang Zhigao;Li Mei;Yu Huaizhong(China Earthquake Networks Center,Beijing 100045,China;Academy of Electronics and Information Technology,China Electronics Technology Group Corporation,Beijing 100041,China;China University of Geosciences,Wuhan 430074,China;Earthquake Agency of the Xinjiang Uygur Autonomous Region,Urumqi 830011,China)

机构地区：[1]中国地震台网中心,北京100045 [2]中国电子科技集团公司电子科学研究院,北京100041 [3]中国地质大学(武汉),武汉430074 [4]新疆维吾尔自治区地震局,乌鲁木齐830011

出　　处：《中国地震》2021年第1期84-94,共11页Earthquake Research in China

基　　金：国家自然科学基金联合基金(U2039205);国家重点研发计划(2018YFE0109700、2018YFC1503506)共同资助。

摘　　要：宽频带地震仪可以连续不断地记录地面振动信号,进而探索地壳振动的变化与地震前兆之间的物理关联性。选取2019年6月17日四川长宁M_(S)6.0地震前后的震中500km范围内15个宽频带地震仪的连续波形数据,通过傅里叶变换计算分析地震前后的地壳振动低频信号(8×10^(-5)~2×10^(-4)Hz)的振幅谱变化,并对低频信号源进行定位,探讨地震前后地壳振动异常演变规律和物理特征。结果表明,长宁M_(S)6.0地震前10天,震源区500km范围内多个地震台的低频信号(8×10^(-5)~2×10^(-4)Hz)出现显著的增强现象,地震前2天出现异常源的集中区域,来源在震源区100km范围内,异常的时间尺度和空间区域与长宁地震基本一致。利用连续波形记录进行地壳振动研究可能对地震短期至短临预报具有重要的参考价值。The ground vibrations are consistently measured by broadband seismometers to explore the physical correlation between the change of ground vibration with earthquake precursor.The continuous waveform data was selected from 15 broadband seismometers within 500km of the epicenter before and after the M_(S)6.0 earthquake in Changning,Sichuan Province on June 17,2019.The amplitude spectrum of low frequency signal(8×10^(-5)~2×10^(-4) Hz)of ground vibration was analyzed by Fourier transform,and the source of the signal is located to study the evolution law and physical characteristics of anomalies before and after earthquake.The results show that the low frequency signal recorded at the several seismic stations in this area is enhanced 10 days before Changning earthquake.The source occurred within the range of 100km in the focal area near 2 days before EQ.The time scale and space area are about same as that of Changning earthquake.We conclude that the analysis of ground vibration using continuous waveform data is essential for the short-term and imminent prediction of earthquake.

关 键 词：长宁地震 地壳振动 地震前兆 低频信号 

分 类 号：P315[天文地球—地震学]