用PS-P走时差方位分布确定转换界面的倾斜状态

Determination of Geometrical Parameters of Oblique Interface by Spatial Distribution of PS-P Travel Time Difference

用几何地震学方法研究了转换界面的倾斜状态对PS-P走时差方位分布的影响。以简明的几何处理给出了倾斜界面上的折射和转换及P波入射点和PS波转换点的解析表达式,通过层间递推关系和射线追踪计算,做出了倾斜Moho面情况下PS_M-P走时差残差方位分布图。与实际观测资料进行比较,以试错法确走赤峰地震台下方Moho界面走向200°,倾角5°,所得结果与人工地震测深结果相符。

The effect of oblique interface on spatial distribution of PS-P travel time difference was studied using geometrical seismology. A group of analytic formulae for the refraction/conversion on the oblique interface and the location of P-to-SV cpnver- sion points were obtained. Through ray traing calculation the diagram for the spatial distribution of the residue of PS-P travel time difference was given. Comparing with the observational data the best fit solution indicates that the Moho beneath Chifeng Seismological Station strikes 200?with its dip angle of 5? which is concordant with the result of explosive seismic prospecting.