2010年元谋Ms5.2地震前地磁极化异常研究

摘要

利用改进的地磁极化方法分析了2010年2月25日云南元谋Ms5.2地震前后楚雄、永胜、通海3个台站的地磁极化值变异系数CZH的变化特征.结果显示:震前3个月,楚雄台地磁极化值出现了显著的剧烈波动,变异系数CZH急剧增大,于震前两个月达到最大,约为正常变化值的2～3倍,震前一个月恢复正常,且该变化主要由垂直分量Z的剧烈波动引起.由于震级较小,在震中距较远的通海和永胜台不存在类似的变化.%The geomagnetic data recorded by the Chuxiong,Yongsheng and Tonghai stations in Yunnan province before and after Yuanmou Ms5.2 earthquake in 2010 were analyzed with improved polarization method,and the coefficient of variation (CV) with polarization value was calculated.The results show that,there is an obvious enhancement of CZH in Chuxiong station in almost 3 months before the Yuanmou earthquake that occurred on 25 February 2010 and recovery on January 2010,and the anomaly reached 2 ～3 times of its normal levels,which may be caused by the vigorous fluctuation of vertical component.However,there was no similar variation exited in the other two stations.