SEISMIC-WAVE ATTENUATION IN ROCKS

A fundamental feature associated with the propagation of stress waves in all solids is absorption of energy, which usually results in a change of the shape of transient waveforms. Despite its importance, the processes by which mechanical wave energy is converted into heat, and its effect on seismic observations, have been poorly understood. Although considerable progress has been made during the past few years, seismic attenuation remains a controversial subject as there is still considerable disagreement between different authors about some of its most fundamental aspects. In the first section of this paper the progress in arriving at a general phenomenological description of wave propagation and related effects such as the frequency dependence of the elastic moduli and transient creep will be covered. It turns out that for most attenuation mechanisms that are significant in rocks, this can be treated relatively independent of the details of the particular physical mechanisms responsible for the energy dissipation, which are treated in the second section. The third section gives a review of experimental results. Copyright 1979 by the American Geophysical Union.