Propagation of acoustic waves through a system undergoing phase transformations

The propagation of a sound wave through a system in which phase transformations are possible is examined. Dispersion and attenuation of the wave are found if the wave frequency is comparable to the reaction rate. Sharp changes in the phase velocity and relative energy loss per cycle are expected when phase boundaries are crossed. The attenuation due to a phase transformation can be sufficiently large to contribute to seismic losses in the mantle.