Volume 3, Issue 6 (June 2006)
Development of an Acoustical Method for Measuring the Transition Layer of Surficial Marine Sediments
A new acoustical method for measuring the physical properties for the transition layer of surficial marine sediments is proposed. In the proposed method, the frequency characteristics of the reflection coefficients for the acoustical normal incidence are utilized. The frequency characteristics of the reflection coefficients are influenced by the depth dependence of the porosity and the density. First, the relationships between the frequency characteristics of the reflection coefficients and the porosity variation with the depth are theoretically shown using Ocean Acoustics and Seismic Exploration Synthesis (OASES) (Biot-Stoll model). Then, the frequency characteristics of the reflection coefficients are measured in water tank and in situ. The measured results are compared with the calculated results using OASES (Biot-Stoll model). Finally, the usefulness of this method is demonstrated.