地壳中张力区对孕震断层的作用

THE EFFECT OF TENSION REGION IN THE CRUST ON THE FAULT IN EARTHQUAKE SORUCE

摘要:

本文应用裂缝的位错理论及位错在应力场中受力的概念讨论了地壳中水平张力区对孕震断层的作用。从理论上计算了位于径向分布的张力区中孕震断层端部所受力的表达式和方向。指出张力区对孕震断层有类似于象力^*的作用。在一定配置条件下,它有利于裂缝的传播,并使裂缝在传播过程中拐弯。地壳底部受一定分布的垂直力作用时,会在其周围产生水平张力区。因此,可以通过地形变资料、孕震断层周围的地质情况去寻找张力区的可能存在区域并分析它对孕震断层可能产生的作用。

Abstract:

In this paper, by applying the theory of dislocation for fracture and the conception of the force acted on the dislocation in stress field, the effect of horizontal tension region in the crust on the fault in earthquake source has been discussed. The formulas and the directions of the forces acted on the ends of the fault in earthquake source located in the tension region distributed radially have been derived theoretically. It is pointed out that tension region has the effect similar to image force for the fault in earthquake source. Under certain dispositions, this effect is to the benefit of propagating of fracture and cause the change of the propagating direction to the fracture. When the bottom of the crust is acted by certain distributed vertical forces, horizontal tension region will be produced at the surroundings. So, according to the datum of surface deformation of the crust and the geological condition around the fault in earthquake source, we could find out the possible existence of tension region and analyse it's possible effect on the fault in earthquake source.