吉林汪清深震前东北地区应变的变化特征分析

Precursor Features of Strain Variation in Northeast China prior to the Deep Focus Earthquake of Wangqing,Jilin Province

2002年6月29日在吉林汪清(北纬43．5°,东经130．6°)发生M_b7．2地震,震源深度593km。本文针对性地对东北地区洞体应变伸缩仪和钻孔体应变近几年观测资料进行了研究。结果表明：2002年6月29日发生的7．2级深源震,东北地区的应变台网观测到了“全压缩应变”的曲线形态,中期前兆异常较为明显,短临前兆异常极为显著。

An M_b 7.2 earthquake occurred in Wangqing,Jilin Province(43.5°N,130.6°E)on July 29,2002,at depth of 593 km.This article studies the recent several years’observing data of the tunnel extension meters and borehole volumetric-strain meters in northeast Chi-na.The result shows that,before the M7.2 deep earthquake of June 29,2002,all the strain stations in northeast China recorded compressional variations in all directions.The mid-term precursor anomaly is quite clear,the short-term precursor anomaly is very striking.