水平层状粘弹性介质中震源应力-应变场的三维边值问题及相应的地电阻率前兆变化的数值模拟

本文应用关于粘弹介质的弹性力学三维有限元方法,研究了定常速率加载边界条件下以断层闭锁模拟震源的“孕震”过程,並将所求得的层状介质应力—应变场与视电阻率的“前兆”变化相关联,以此给出该“孕震”过程中地表视电阻率“前兆”变化的时空分布,从而揭示水平层状介质视电阻率的变化与震源区应变场之间的关系。计算结果表明,粘弹性介质的存在,对孕震过程起着相当重要的作用。介质中应力集中程度与材料粘弹性有着密切的关系。另一方面,对于视电阻率前兆而言,其时空分布不仅与大范围的应力—应变场有关,而且还与台站探测范围内介质的力学、电性结构条件相关联。

MATHEMATICAL MODELLING OF THE 3-D BOUNDARY CONDITION PROBLEM OF SOURCE STRESS-STRAIN FIELD IN HORIZONTAL LAYERED VISCO-ELASTICAL MEDIUM AND THE CORRESPONDING PRECURSORY CHANGES IN EARTH RESISTIVITY

This paper takes the concentration of stress in a locked fault as the model of earthquake source and deals with the changes in the stress field in a three layered media under the lateral boundary condition of a constant rate of displacement loading. The "precursory" changes in apparent resistvity at the surface of the media associated with the changes in stress-strain field is also discussed in this paper in order to reveal the possibil way of connecting the spatial-temporal changes in apparent, resistivity to the source process.The results show that, the existance of viscous material in the media would play a very importont role in the preparatory process:besides of the influence of structure of the media the extent of stress concentration is closely relative to the viscous property of the media also, And the spatial-temporal distribution of apparent resistivity precursor is not only concerned with the stress-strain field but also with the mechanical and electrical structure condition of media within the detective scalein observational stations.