Abstract: Near-surface earth resistivity and underground water level anomalies were recorded at Qingdao seismic observatory of Shandon Province before and after the M_S 8.0 Wenchuan Earthquake of May 12,2008.The observation data of the earth resistivity at the observatory revealed that the underground water level dropped and the resistivity increased.It is postulated that in the special tectonic setting as Qingdao observatory,the variation of stress and strain resulted in the change of water level beneath the station,leading to the variation of resistivity.The relationship between the variation of stress field and the change of earth resistivity before earthquake is analysed.

Key words: Wenchuan M_S 8.0 Earthquake, earth resistivity, underground water level, stress field

摘要： 分析了2008年5月12日汶川M_S8.0地震前山东省青岛地震台地电阻率和地下水位的异常变化。对比发现,地电阻率与地下水的异常起始时间一致,其中,地下水位下降,地电阻率上升,推测产生异常的原因是,该观测区位于断裂破碎带附近,构造变形引起地下水或含水度变化的响应敏感,进而引起地电阻率的变化。此外,文中对地震前应力场的变化与电阻率的变化之间的关系也进行了探讨。

关键词: 汶川M_S8.0地震, 地电阻率, 地下水, 应力场