ABSTRACT Results from a series of laboratory geotechnical and acoustical tests on carbonate sediments from the Western Indian Ocean are presented. With these data, empirical relationships for variations in porosity (Φ) and compressional and shear wave velocity (V p and V 5 ), with effective stress (σ'), were established. With an σ' vs. depth (z) profile, nontemperature-corrected empirical equations for V^ and V s vs. z were then obtained. These data cover cover only the upper 100 m of sediments. An empirical equation for the variation of shear modulus (G) with z is then established. This is shown to be dominated by the variation of V s with z. The importance of these equations in developing geoacoustical models of the seafloor, which accurately represent in-situ conditions, is assessed. A check of internal consistency was made: values of V p were calculated with V 5 vs. σ' and Φ vs. σ' equations in Gassmann's theory, and comparisons are made with V^ vs. σ' empirical predictions. Uncertainty bounds were calculated for the Gassmann V p predictions, and it was found that empirical V p predictions were close to the upper limits of the Gassmann V^ predictions. We therefore concluded that a partial verification of the internal consistency of the empirical equations was demonstrated
