砂岩在摩擦滑动中的电阻率变化及其在地震预报中的应用

RESISTIVITY CHANGES IN THE FRICTIONAL SLIDING EXPERIMENTS OF SANDSTONE SAMPLES AND THEIR APPLICATION IN THE STUDY OF EARTHQUAKE PREDICTION

摘要:

用双剪法对小浪底砂岩在摩擦滑动中的电阻率变化进行了实验研究。结果表明,在摩擦滑动过程中,电阻率"趋势"变化有明显的方向性效应,在不同的测量方位上显示出较大的差异性和不同的前兆特征。平行于断层面的第Ⅰ道电阻率持续上升,大滑动前无明显异常反应;垂直横跨断层面两侧的第Ⅱ道随剪应力的增大电阻率由开始大幅度下降转为平稳变化,大滑动前出现清晰的突变异常,其幅值达50%左右;与断层面斜突成45°夹角的第Ⅲ道随剪应力的增大电阻率缓慢上升,达到某一极值后随块体的滑动转为下降。最后,本文简单地讨论了产生这些差异性现象的可能原因及其在地震预报中的应用。

Abstract:

The results of experimental study on resistivity changers of the Xiaol-langdi sandstone samples with the bilateral shear method are presented in this paper.
The main feature of the results is that the trends of resistivity changes in different directions with respect to the loading direction are different during the loading process up to sliding. The resistivity increases steadily in the direction parallel to the loading direction but no change in the trend prior to the main sliding; the resistivity in the direction perpendicalar to the loading direction firstly decreases with big magnitude, then with small magnitude as loading stress increases and clearly shows the behavior of a sudden anomalous change right before the main sliding with the magnitude of 5.0%; the resistivity in the direction which is 45° with respect to the loading direction shows a trend of slow increases and after the trend reaches a maximum value it decreases. Furthermore, this paper also deals with possible causes of these results and their application in the study of earthquake prediction.