title: Attenuation of sound in sand sediments due to porosity fluctuations.
abstract: At high frequencies, the attenuation measured in sand sediments is larger than that predicted by Biot theory. To account for this discrepancy, perturbation theory is used to incorporate losses due to scattering by porosity variations into both Biot's poroelastic equations and the effective density fluid model. While previous results showed that fluctuations in the bulk frame modulus were insufficient to produce significant attenuation in a sand sediment, modest levels of fluctuations in the porosity produce significant scattering loss. By using the sediment parameters and the heterogeneity power spectrum measured during the Sediment Acoustics Experiment in 2004, the perturbation theory result shows good agreement with the sound speed and attenuation data without any free parameters.
authors.affiliation: Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Hefner
authors.affiliation: Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105.
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Jackson