弱裂隙各向异性对地震体波的效应

The Effects of Weak Crack induced Anisotropy on Seismic Body Waves

由数值模拟证明，尽管对地震体波走时及纵波动力学特征来讲，弱裂隙各向异性的影响可以忽略，但与各向同性介质中的横波相比，即使对弱裂隙介质，穿透其中的横波的偏振特征也会出现显著的不同。这种不同，突出地表现为横波在入射面内的振动与垂直入射面内振动的相互耦合。在相当宽的横波主频范围内，弱裂隙各向异性对横波三分量波形特征的效应不会消失。三分量记录横波的偏振分析在横波的理论研究和观测解释中将起重要的作用。

From numerical modelling,it can be demonstrated that the weak crack induced anisotropy introduces the polarizations of two quasi shear waves of splitting different from that of the shear wave propagation isotropiclly,although its effects on the seismic traval time and P wave feature could be ignored.Such difference appears as the coupling between the motions in the incident plane and that orthogonally.In the wider range of shear wave dominent frequency,the effects of the weak anisotropy on shear waves can not disappear.The polarization analysis on the three componenet records will play an important role for theoretical study and observation interpretation to shear wave.