地震动态触发机制的初步研究

提出地震的动态触发模式。用三维非线性动态有限元方法研究了地震的动态触发的可能机制。模拟结果表明，应力波在反射后发生半波损失，压缩波可以转变成拉伸波，反之亦然。因此，动应力包含有拉伸应力。拉伸波叠加或干涉形成较大的动态应力，减小围压，因此减小了内摩擦力，从而触发地震，研究表明断层形态会影响动态应力，认为地震触 发的位置与孕震体边界形状有关。本文还结合有关地学理论和资料，对以上结果进行了相应的分析并给出物理解释。

A preliminary study on mechanism of dynamic tiggering of earthquakes

We propose a possible dynamic mechanism of earthquake triggering. Three dimensional nonlinear FEM is adopted to study the mechanism and the dynamic process of earthquake triggering. Simulation result shows that the dynamic mechanism is quite different from the static one. Especially, the reflected compressive waves, having lost half wavelength, become tensile ones which can be superposed each other to double the tensile stress and cause a rupture. Considering the giant ambient pressure, therefore, the mechanism may be like this: the tensile stress reduces the ambient compressive static stress to reduce the inner friction and cause an earthquake. Study suggests that triggering position should be relied on the boundary shape of a rock body. And an interpretation is given by a joint analysis in conjunction with observations.