Vertical porosity and velocity fluctuations in shallow-water surficial sediments and their use in modeling volume scattering

Abstract

Variability in sediment porosity and velocity creates volume scattering which is a parameter used in high-frequency scattering models. High-resolution vertical profiles of sediment porosity and compresstonal wave velocity collected from 17 diverse sites on continental shelves are used to calculate vertical autocorrelanon functions. Porosity and velocity fluctuations in the upper 20-35 cm of sediment exhibit correlation lengths which are highly variable. The variance of the porosity fluctuations varies with sediment type. Data comparisons indicate that fluctuations in sediment porosity are due to biological and sedimentological processes and fluctuations in sediment velocity are due to hydrodynamic processes