武都分量钻孔应变在汶川MS8.0级地震前的异常变化分析

通过对武都应变台多年应变资料的处理分析后发现,在汶川8.0级地震发生前,武都台应变有显著的前兆异常变化,它与昆仑山口西8.1级地震前出现的异常有很高的相似度.昆仑山口西地震和汶川地震前都有“α-β-γ”形变阶段,在不同的前兆异常阶段,异常形态有明显的差异,而且各具特点.尤其在β1阶段,EW道、面应变、差应变的异常变化（中期异常）都出现在震前2-3年,持续时间约1年多,而且异常都非常显著.本文详细分析了武都台应变在各个阶段的前兆异常变化特征,并就其原因进行了初步分析.

Component Borehole Strain Changes at Wudu Station Before the Wenchuan 8.0 Earthquake Analysis

Through analyzing strain monitoring data from Wudu station,the significant anomaly was found before the Wenchuan 8.0 earthquake,and such anomaly is very similar with the phenomena before the Kunlun mountain 8.1 earthquake.There existed a ＂α-β-γ＂ pattern of deformation stages before both Kunlun earthquake and Wenchuan earthquake.At the different stages of precursory anomalies,abnormal shape is significantly different,especially in the β1 stage,during which the EW channel,plane strain,differential strain changes （interim） before 2 to 3 years,lasting for about 1 year.At different stages,precursory anomalies have remarkable difference.In this article we analyzed the monitoring data from Wudu station to characterize the strain precursory anomaly for each stage,and discussed the possible causes and mechanism between the anomalies and occurrence of the earthquakes.