摘要
The stress field, controlling the developmental process of a shallow focus inland earthquake, is regarded as the superposition of the fundamental and the variational stress field, but the latter often plays an important role. In this paper we focus on two kinds of problems generating the variational stress field, which is related to geotherm. One is the local high temperature region problem, which includes the situations of the heat carrying fluid intruding into the vertical or horizontal cracks and the case of existence of the static state local high temperature region. The other is the problem that the thermal energy is released as the fault emerges displacement discontinuities,during the steady state extension. The two problems can be idealized into the three dimension thermoelastic quasi static problems and their solutions can be given, respectively. Thereby,we may obtain the approximate expressions of some additional seismic precursor fields generated on the plane near the ground surface,for examples, the temperature, the body strain and the underground water, the vertical deformation and the ground tilt vector fields etc. We discuss their space time distribution feature on the plane and get some qualitative results by contrasting them with each other. lt may provide some clues for further studying the comprehensive applications of the preseismic observations.
The stress field, controlling the developmental process of a shallow focus inland earthquake, is regarded as the superposition of the fundamental and the variational stress field, but the latter often plays an important role. In this paper we focus on two kinds of problems generating the variational stress field, which is related to geotherm. One is the local high temperature region problem, which includes the situations of the heat carrying fluid intruding into the vertical or horizontal cracks and the case of existence of the static state local high temperature region. The other is the problem that the thermal energy is released as the fault emerges displacement discontinuities,during the steady state extension. The two problems can be idealized into the three dimension thermoelastic quasi static problems and their solutions can be given, respectively. Thereby,we may obtain the approximate expressions of some additional seismic precursor fields generated on the plane near the ground surface,for examples, the temperature, the body strain and the underground water, the vertical deformation and the ground tilt vector fields etc. We discuss their space time distribution feature on the plane and get some qualitative results by contrasting them with each other. lt may provide some clues for further studying the comprehensive applications of the preseismic observations.
