Abstract
Phase velocity of plane Rayleigh waves on a transversely isotropic, heterogeneous medium is calculated by integrating directly the equations of motion. The group velocity is calculated directly from the energy equation.
The increments of the phase velocity with respect to the changes of the physical parameters are calculated by the variational calculus. It is shown that this prediction of the phase velocity increment is useful for small changes (up to 10%) of the physical parameters.
