地电台址大范围介质条件的数值模拟研究

MATHEMATICAL SIMULATION RESEARCH OF AFFECT OF LARGE SCALE MEDIUM CONDITION ON THE OBSERVATION OF GEOELECTRICAL STATION

摘要:

本文取两类震源模型,即"闭锁"模型和"膨胀"模型进行数值模拟,计算了大范围层状介质在多种不同组合情况下,其应力、应变场的分布,并进而计算了由附加应力、应变产生的视电阻率变化量。结果表明,不同介质组合对地电阻率前兆异常观测的影响不同,有利于发现前兆异常的大范围介质条件是:(1)坚硬层孕震;(2)孕育地震的高强度坚硬层要薄;(3)地表疏松覆盖层不能太厚。此外,计算结果还表明,地电台站探测范围内的介质力学,电性条件对前兆异常观测也有重大影响。

Abstract:

For two types of earthquake focus model ("locked fault" and "expanding ball" models), the distributions of stress and. strain were calculated separately for different combinations of large scale layer medium, then the resistivity anomalies caused by additional stress and strain were calculated in order to reveal the affect of large scale medium condition on the observation of geoelectrical station. The results show that the change of combination of lrage scale layer medium has great affect on resistivity anomaly, and the good conditions are:(1) potential for earthquake should happen in hard rock layer; (2) the thiner of such hard rock layer, the better; (3) the depth of soft covering layer should not be too thick. Besides, the results show that the local medium combination and its mechanic and clectrical characteristics also have great affect on resistivity anomaly.