Shear wave velocity measurements in high porosity marine sediment models using radiation impedance method

Abstract

Acoustic measurements of surficial high porosity marine sediment are important to investigate the coastal environments. To do this, the measurement of shear wave velocity rather than longitudinal wave velocity is useful for determining the physical properties of surficial high porosity marine sediment. However, the direct measurement of shear wave velocity in high porosity marine sediment is very difficult, because the attenuation of the shear wave in high porosity marine sediment is quite large. In this study, shear wave velocities in four kinds of high porosity marine sediment models are measured using the radiation impedance method which has been proposed. From the measured results, it is seen that the shear wave velocity of below 1 m/s can be measured, and the shear wave velocity increases, as the porosity decreases. The relationship between the shear wave velocity and the porosity are different depending on the kind of marine sediment model.