华北地区强震前电磁短期异常特征研究

Research on Short-Term Abnormal Characteristics of Strong Earthquakes in North China

利用空间线性度方法对强震近震中区的多台地电阻率、地磁Z等观测资料进行组合计算 ,得到描述强震前近震中区前兆场的新特征量———空间线性度α。分析计算了华北地区发生的 8次 5 5级以上强震前的地电、地磁观测资料 ,结果表明 ,强震前半年内震源区附近的α有明显的下降异常变化。

Using the measurement of the spatial linearity to calculate the geoelectrical resistivity and the geomagnetism datum of Z direction of some stations near epicenter of strong earthquake,we can find the new premonitory characteristic value——spatial linearity short-term abnormal characteristic value(α) which describes premonitory field in the epicenter district before strong earthquake. By analyzing the datum of geoelectrical resistivity and the geomagnetism datum of Z direction in 8 strong earthquakes with M≥5.5 previously occurred in north China, we can conclude that the spatial linearity(α) will decline obviously in the earthquae cource district before half an year of the strong earthquake.