Quasi-spherical approach for seismic wave modeling in a 2-D slice of a global Earth model with lateral heterogeneity

[1] For iterative calculations of synthetic seismograms with limited computer resources, a fast and accurate modeling method is needed. Axisymmetric modeling has often been used in global seismology to restrict computational time and storage. This approach can correctly model 3-D geometrical spreading effects with computational times comparable to 2-D methods, but cannot treat asymmetric structures about the source axis. To overcome this problem, a new approach is proposed for seismic wave propagation in a 2-D slice through a global Earth model with lateral heterogeneity. The elastodynamic equation for spherical coordinates is not solved in the conventional spherical domain but instead in the ‘‘quasi-spherical domain’’ using the finite-difference method. The validity and efficiency of this technique is illustrated with numerical examples including subduction zone structures. Citation: Toyokuni, G., H. Takenaka, Y. Wang, and B. L. N. Kennett (2005), Quasi-spherical approach for seismic wave modeling in a 2-D slice of a global Earth model with lateral heterogeneity, Geophys. Res. Lett., 32, L09305, doi:10.1029/2004GL022180.