含粗糙面断层的远场体波辐射

FAR-FIELD BODY-WAVE RADIATION OF THE FAULT WHICH CONTAINS ASPERITIES

摘要:

本文用位错模式研究了含粗糙面断层的远场地震体波辐射。假设粗糙面大小和整个错动面大小的比值为C,并假设破裂从中心开始,计算了不同C值对远场地震波谱的影响。结果表明,与均匀圆盘状断层的远场振幅谱相比,不同之处是,由于粗糙面的存在,当裂纹前端传播至粗糙面的边缘处时,引起波谱开始部分的分裂,表现在谱的第一个波谷处。粗糙面的大小对振幅谱的影响不显著。另外,比较P波和S波振幅谱,发现S波波谱的拐角频率比P波的低。

Abstract:

In this paper, the far-field body wave radiation of the fault which contains a asperity is studied by using dislocation model. Assuming that the ratio of the asperity size to the size of whole dislocation surface is C. and the fracture begins in the center, it calculates the effect of different C-values on the far-field seismic wave spectrum. The results show that comparing with the far-field amplitude spectrum of even penny-shaped fault because of the existence of asperity, it, is different that it causes the splitting of beginning part of wave spectrum in the first wave base when the fracture propagates to the fringe of the asperity. It is obvious that the asperity size effects on the amplitude spectrum. In addition, comparing P-wave spectrum with S-wave spectrum, it is found that the corner frequency of P-wave is higher than that of S-wave.