In Situ Determinations of the Velocities of Compressional and Shear Waves in Marine Sediments from a Research Submersible


Book Description

In situ measurements were made of the velocity and attenuation of compressional waves and of velocities of Stoneley waves (from which shear-wave velocities were computed) at six stations in the sea floor off San Diego, California. Water depths ranged from 20 to 1130 meters, and sediment types ranged from medium sand to clayey silt. Sediment densities, porosities, and grain sizes were measured in samples taken at each station. The unique data obtained allowed tentative evaluations of models and equations, and computation of constants, for elastic and viscoelastic saturated, porous media. (Author).
















Acoustic Relaxation in Unconsolidated Marine Sediments


Book Description

Acoustic relaxation theory for visco-elastic media provides for sound propagation in unconsolidated marine sediments. For the frequency range of 14 to 200 kHz, dispersion for compressional-wave and shear-wave velocity is negligible for all practical purposes, but sound absorption shows significant changes. (Author).




Acoustic and Related Properties of the Sea Floor


Book Description

The general objectives of this investigation were to determine and study those characteristics of the sea floor that affect sound propagation and the prediction of sonar performance; to support underwater acoustics' experiments and theory by furnishing information on the mass physical properties of sediments and rocks in the form of geoacoustic models of the sea floor; and to develop models of the sea floor which include gradients of sound velocity and attenuation, density, and elastic properties. Specifically, the minor objectives were to revise and review earlier work on the relations between frequency and attenuation of compressional (sound) waves in marine sediments and on the relations between attenuation and sediment porosity. The major objectives were to determine and predict variations of the attenuation of sound waves with depth in the sea floor.