Scattering of elastic waves in media with a random distribution of fluid-filled cavities: theory and numerical modelling
Date
2004
Authors
Hong, Tae-Kyung
Kennett, Brian
Journal Title
Journal ISSN
Volume Title
Publisher
Blackwell Publishing Ltd
Abstract
The propagation of elastic waves is modelled in media with a random distribution of fluid-filled circular cavities, which display high physical impedance in contrast to background media. Theoretical attenuation expressions for media with circular cavities, which may be filled with any material (e.g. vacuum, fluid, elastic materials), are formulated using an ensemble treatment for first-order transmitted waves. Numerical estimates of scattering attenuation rates agree with the theoretical results well. The scattering attenuations (Q-1) are proportional to the scale of cavities and the number density (η, number of cavities per area in a medium). The decrease of primary energy with the size of cavities does not result in the increase of coda energy owing to the increase of both purely backscattered waves from cavities and the trapped waves inside cavities. Scattering properties (e.g. scattering attenuation, coda energy, phase fluctuation of primary waves) in media with randomly distributed cavities are very different from those in stochastic random media. It appears that heterogeneities with high impedance in the earth may not be well represented with stochastic random heterogeneities.
Description
Keywords
Keywords: cavity; elastic wave; fluid pressure; seismic attenuation Attenuation; Elastic waves; Numerical modelling; Scattering; Single scattering theory; Wavelet-based method
Citation
Collections
Source
Geophysical Journal International
Type
Journal article