HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Takenaka, H. Articles by Kennett, B. L. N. Search for Related Content GeoRef GeoRef Citation

An efficient approach to the seismogram synthesis for a basin structure using propagation invariants

Department of Earth and Planetary Sciences Faculty of Science Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-81, Japan
Obayashi Corporation Technical Research Institute, Shimokiyoto 4-640, Kiyose, Tokyo 204, Japan
Earthquake Research Institute The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113, Japan
Research School of Earth Sciences Australian National University, Canberra ACT 0200, Australia

Abstract

The Aki-Larner method is one of the cheapest methods for synthetic seismograms in irregularly layered media. In this article, we propose a new approach for a two-dimensional SH problem, solved originally by Aki and Larner (1970). This new approach is not only based on the Rayleigh ansatz used in the original Aki-Larner method but also uses further information on wave fields, i.e., the propagation invariants. We reduce two coupled integral equations formulated in the original Aki-Larner method to a single integral equation. Applying the trapezoidal rule for numerical integration and collocation matching, this integral equation is discretized to yield a set of simultaneous linear equations. Throughout the derivation of these linear equations, we do not assume the periodicity of the interface, unlike the original Aki-Larner method. But the final solution in the space domain implicitly includes it due to use of the same discretization of the horizontal wavenumber as the discrete wavenumber technique for the inverse Fourier transform from the wavenumber domain to the space domain.

The scheme presented in this article is more efficient than the original Aki-Larner method. The computation time and memory required for our scheme are nearly half and one-fourth of those for the original Aki-Larner method. We demonstrate that the band-reduction technique, approximation by considering only coupling between nearby wavenumbers, can accelerate the efficiency of our scheme, although it may degrade the accuracy.