The Propagation of Surface Waves in Anisotropic Media

Surface wave propagation in examples of unlayered and multilayered anisotropic media is examined numerically with a programme using an extension of the Thompson-Haskell matrix formulation. Surface wave propagation in an isotropic earth model containing an anisotropic layer in the upper mantle has been found, for the most part, to differ very little from propagation in a purely isotropic model. An exception is the propagation of the third generalized mode (corresponding to the second Rayleigh mode in isotropic structures), which has particle motion differing considerably from motion in isotropic media. Observations of such particle motion in the Earth have been made.