吉林通化地震台四分量钻孔应变在日本9.0级地震前后的变化特征

基于通化地震台四分量应变观测,通过K-L最佳直线拟合及傅立叶滑动去年周期对数据进行处理,进一步分析日本9.0级地震前后应变变化特征。结果表明,K-L最佳直线拟合和傅立叶滑动去年周期,可以较好地消除通化台应变观测中的长趋势变化项和年变成分,使应力应变的微动态变化更加显著地表现出来;通化台四分量应变在日本9.0级地震前的压性变化与同一构造带的另外两个台站分量应变观测的大幅压性变化一致;日本9.0级地震使通化台面应变出现持续约8个月左右的扩张变化,变化性质与由GPS计算得到的同震位移结果较为一致。

Variation of 4-Component Borehole Strain at Tonghua Seismological Station,Jilin,Before and After the Japan M9 .0 Earthquake

Based on observation of 4-component borehole strain in Tonghua ,variation characteristics of strains before and after the Ja-pan M9 .0 earthquake are analyzed after the data is processed by the way of K-L best straight line fitting and Fourier slide for remo-ving yearly period .The results show that K-L best straight line fitting and Fourier sliding for removing yearly period can eliminate long trend and annual changes in strain observed at Tonghua Station and make the micro dynamics variations of stress and strain more obvious .The compressive changes of 4-component strain at Tonghua Station are consistent with strain at the other two stations in the same structural belt before Japan M9 .0 earthquake .The surface strain at Tonghua Station caused by Japan 9 .0 earthquake had expanded for 8 months ,which consistent with coseismic displacement calculated by GPS .