Acoustic and physical property relationships in marine sediment

Abstract

I n situ sediment acoustic impedance measured from a ship underway is being used to infer the physical properties of the sea bed. These inferences rely on published regression relationships developed to estimate impedance from sediment density or porosity. Thus the equations must be rearranged to yield the desired parameter when impedance is known. Rearranging or inverting regression equations is not a valid technique. It is justified only when properly derived equations are unavailable. Herein are regressions of sediment density, porosity, and mean grain size on impedance to complement relationships already in the literature. Presented also are data and methods to place confidence limits on the predictions.