天然地震PS转换波动力学特征的初步研究

本文根据合成理论地震图的广义射线理论,并应用自行编写的FORTRAN计算程序,研究了单一界面、薄层和迭层界面上形成的PS转换波的动力学特征,讨论了沉积盖层及上部地壳介质吸收对转换波的影响。

STUDY ON THE DYNAMIC CHARACTERISTICS OF PS CONVERTED WAVES

In recent years, some important results have been obtained in the research of the crust and upper mantle structures by use of PS converted waves. In this paper the dynamic characteristics of the PS converted waves from a single discontinuity, thin layers and stack of thin layers are studied based on the generalized ray theory of the synthetic seismogram. The corresponding FORTEAN program was written by us. The effects of medium absorption for converted waves in the sedimentary layer and upper crust was discussed as well.The results indicate that the PS wave form generated at the single discontinuity, the thin layers and the stack of thin layers is similar to that of the primary P wave; the period of PS waves in the short-period seismogram is about 1.0 second which is related to the structures, but its variation is very small; the amplitude ratio of PS waves to P wave is 0.1-0.6 or more. The relative energy of PS waves increases in the region with sedimentary layers. The absorption of the medium has a strong effect on the PS wave's energy. Computational results in this study are roughly consistent with field observations. These provide a theoretical basis for identification of PS phases and interpretation of the data.