标题： 强地震前各向异性变化的观测证据 显示英文标题

标题： Observational evidence of anisotropic changes apparent resistivity before strong earthquakes

摘要： 基于归一化月变化率的方法，我们研究了两次强震震中区域事件发生前七个观测站的电阻率数据。 各向异性视电阻率的变化与最大主应力方位之间的关系进行了分析。 研究表明，在最大主应力方位垂直的方向上出现显著的视电阻率变化，而在最大主应力方向上仅记录到较小的波动。 我们推测，各向异性电阻率的变化发生在强震发展的后期阶段，可以在震中区域观察到。 如果增加观测站的密度，并且观测电阻率的方向正确，那么可以通过观测到的电阻率异常来估计地震震中位置。 显示英文摘要

摘要： Using a method based on normalized monthly variation rate, we studied resistivity data of seven observation stations before the events in the epicenter areas of two strong earthquakes. The relationship between variation of anisotropic apparent resistivity and the azimuth of the maximum principal stress is analyzed. The study shows that significant apparent resistivity variation occurs in the direction that is perpendicular to the azimuth of the maximum principal stress while only small fluctuation are recorded in the direction of the maximum principal stress. We surmise that the variation of anisotropic resistivity occurs in the late stage of the development of a strong earthquake, which can be observed in the epicenter area. If the density of the observation stations is increased and the direction of the observed resistivity is right, the epicenter of an earthquake location may be estimated by the observed resistivity anomaly.