An elastic approximation of seabed acoustics and its connection to consolidation in the New England Mud Patch

The purpose of this study is to estimate the consolidation of sediments from measured wave speeds and attenuations, through parameter fitting of acoustic propagation models, particularly visco-elastic models. Consolidation is quantified by Pride's consolidation parameter, which is directly related to the ratio of the static frame bulk modulus to the grain bulk modulus. In physical terms, it represents the static mechanical stiffness of the skeletal frame of a porous medium. The effects of consolidation are demonstrated with the data from the New England Mud Patch, specifically mineralogy and acoustic data are used to invert for model parameters, particularly the frame bulk modulus, from which consolidation is calculated. Ideally, a porous medium model should be used, but an elastic approximation, which has fewer input parameters, is more efficient. In the process of doing so, an improved elastic approximation model was developed. It is shown that, at the New England Mud Patch, using the improved elastic model inversion, consolidation is shown to increase monotonically with depth.