腾冲台强震前地电场线性极化特征  

Linear polarization feature of geoelectric field before strong earthquakes at Tengchong station

作　　者：张学民[1] 卢军[2] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]中国地震台网中心,北京100036

出　　处：《地震》2007年第2期89-98,共10页Earthquake

基　　金：国家科技攻关项目(2004BA601B01-05-03)

摘　　要：分析了位于云南西南部的腾冲地震台自1986年以来的大地电场记录资料,分别针对4次远强震和中等地方震前的电场极化特征进行了分析。结果表明,在地震发生前3个月的时间内,电场极化逐渐趋于线性,而不象正常时段时数据分布比较分散。地震越强,其线性极化特征出现得越早。电场异常的方向性与震中方位有一定关系,但也与震源区的活动断裂走向有关。综合分析了异常产生的机理,认为异常可能来自震源,而震源区构造是信号传播的最佳通道。电场的震前线性极化异常具有非常典型的短临性,对未来地震方位及时间预测具有一定的参考价值。The geoelectric data recorded at Tengchong station located in southwest Yunnan province since 1986 were analyzed. Aiming at the polarization feature of geoelectric field before 4 distant and moderate local earthquakes, the results show that the polarization of geoelectric field gradually became linear during 3 months before earthquakes, which is different from the normal times when the data were discrete. The stronger the earthquake was, the earlier the linear polarization feature occurred. The polarization direction of geoelectric field was related to the azimuth of the epicenters, while there is close connection with the striking of active faults in focal area. Synthetically analyzing the mechanism of this kind of anomalies, it is thought that the anomalous geoelectric field signals might come from the focus and the fractures in focal area might be the best channel for the fluid flowing and propagation. The preseismic linear polarization feature of geoelectric field is typically imminent, which is of some significance in location and time prediction of future earthquakes.

关 键 词：地电场 腾冲台 线性极化 短临预报 

分 类 号：P315.7[天文地球—地震学]