Parametric modeling with beamspread compensation and MIMO frequency domain inversion applied to fine saturated sands

A system identification technique is applied to estimate the intrinsic absorption and dispersion of two fine sands. The method is based on the parametric modeling of the wave propagation through a Plexiglas tank filled with the sediment under investigation. The applicability of various porous models is discussed. The viscoelastic constant Q model and viscoelastic rational form model are applied and compared. Closed form expressions describing the wave propagation are replaced by Debye series expansions with correction coefficients that consider the beamspread caused by the finite aperture of the emitter. A multiple input multiple output (MIMO) representation is used in conjunction with the maximum likelihood estimator (MLE) for the estimation of the sediment parameters. The estimated absorption and dispersion curves are depicted.