2019年6月17日长宁MS6.0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 MS6.0 Earthquake

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_S6.0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^-4Hz）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_S6.0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^-4Hz）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。

Abstract:

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_S6.0 earthquake in Changning,Sichuan Province on June 17,2019. The amplitude spectrum of low frequency signal(8×10^-5～2×10^-4Hz) 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.