Peculiarities of surface wave fields in laterally inhomogeneous media in the framework of ray theory

The paper presents the results of numerical modelling of Love waves in a layer with varying thickness over a homogeneous half-space. Rays, amplitudes of a transient wave, and synthetic seismograms were calculated by the use of the space-time ray method. It is shown that the lateral heterogeneity strongly affects the surface wave field: the seismograms at two near-by points at the same epicentral distance differ markedly. Anomalies in the Rayleigh and Love wave polarization are analysed by treating the second term in the series, representing the surface wave field in a laterally heterogeneous medium. The effects of lateral heterogeneity on the polarization are similar to those for body waves.