The dispersion of surface waves on multilayered media*

TLDR

Surface wave dispersion on multilayered media is investigated using Thomson’s matrix formalism. The authors compute Rayleigh wave phase and group velocities for simplified continental crust models and compare the resulting group velocity curves with published measurements. Observed group velocity scatter exceeds the differences among the model curves, indicating that horizontal crustal heterogeneity, rather than measurement error alone, accounts for the variability.

Abstract

abstract A matrix formalism developed by W. T. Thomson is used to obtain the phase velocity dispersion equations for elastic surface waves of Rayleigh and Love type on multilayered solid media. The method is used to compute phase and group velocities of Rayleigh waves for two assumed three-layer models and one two-layer model of the earth's crust in the continents. The computed group velocity curves are compared with published values of the group velocities at various frequencies of Rayleigh waves over continental paths. The scatter of the observed values is larger than the difference between the three computed curves. It is believed that not all of this scatter is due to observational errors, but probably represents a real horizontal heterogeneity of the continental crusts.