Synthetic Seismograms in Heterogeneous Elastic Waveguides and Applications in Investigating LG-Wave Propagation

摘要

This study is aimed at development and application of a new wave propagation and modeling method for regional waves in heterogeneous crustal waveguides using one-way wave approximation. As the first step, we solve the 2D SH-wave problem. A half-space GSP (Generalized Screen Propagator) is formulated for the SH half space problem. We apply our method to simulating regional wave propagation in different types of complex crustal waveguides including those with small-scale random heterogeneities and random rough interfaces of sedimentary layers. Synthetic seismograms and snapshots are shown to facilitate the study of path effects of Lg waves. Slowness domain analysis is especially useful in investigating energy transfer in crustal waveguides and for determining which part of the energy can be trapped in the waveguide. The influence of crustal heterogeneities and rough interfaces on Lg amplitude attenuation and Lg coda formation are studied.