Gaussian Beam 法を用いた不整形地盤中のやや長周期地震波の解析

Abstract

In this paper, the Gaussian beam aproach to surface wave propagation proposed byYomogida is used to examine surface waveforms in a laterally heterogeneous medium. TheGaussian beam formulations for surface waves in a laterally slowly-varying medium is firstlyexplained in detail. Numerical example is conducted by forward modelling of Love waves fora heterogeneous Imperial Vallley structure. The prototype event assumed is the 1968 BorregoMountain earthquake. As a site, El Centro is chosen. Ray tracing of Love waves and thecontributions of each Gaussian beam to the synthetic seismogram are examined. The resultsindicate the good sensitivity of the present method to the details of laterally heterogeneity.