Normal mode computation by the generalized reflection_transmission coefficient method in planar layered half space
利用广义反射-透射系数方法求解含低速层水平层状介质模型中面波频散曲线问题

We present a new approach to calculation of dispersion curves and normal mode solutions of multilayered solid earth model with low velocity layers based on the generalized reflection-transmission coefficient method. It is efficient to tackle these two problems by utilizing the single top-layer secular function proposed by Chen in 1993. However, some lower order modes are difficult to be obtain by merely using the single top-layer secular function due to numerical singularity while the earth model contains low velocity layers. In this paper, we propose using the secular function set, instead of the single secular function, to solve this problem. With the secular function set, different modes can be calculated respectively through corresponding secular functions. Numerical experiments show that the new approach is efficient, stable and reliable, thus it makes the generalized reflection-transmission coefficient method applicable to computation of normal modes in various stratified earth models.