Bulletin of the Seismological Society of America; August 1982; v. 72; no. 4;
p. 1143-1153
© 1982 Seismological Society of America
Resonant scattering by fluid-filled cavities
GEORGE A. MCMECHAN
EARTH PHYSICS BRANCH DEPARTMENT OF ENERGY, MINES AND RESOURCES PACIFIC GEOSCIENCE, SIDNEY, BRITISH COLUMBIA V8L 4B2 Canada
Abstract
Interaction of seismic energy with a fluid-filled cavity results both in scattering by the cavity and in excitation of its normal modes. The normal modes contain information about the properties of the fluid that fills the cavity and its size. In the frequency domain, each mode in the cavity response can be decomposed into a sum of two spectra; the "background" scattering from an empty cavity and the resonant coupling between the fluid cavity filler and the surrounding matrix. Synthetic seismograms are computed by Fourier transformation and summing modes. The theory is applied to a water-filled crack in granite, a model for the core of Mars, and a magma chamber.
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