Low-frequency attenuation of acoustic waves in sandy/silty marine sediments

Abstract

Sandy/silty marine sediments are water saturated and consist of diverse tiny rock pebbles. The weight of higher pebbles holds lower pebbles in contact. For low-frequency acoustic disturbances, the no-slip condition and viscosity cause the local water displacement near solid surfaces to be nearly the same as that of the neighboring pebbles. Water farther from surfaces oscillates relative to solid matter because of mass density difference, and viscosity limits the oscillation amplitude. Derived dissipative wave equation predicts attenuation proportional to frequency squared, proportional to the square of the difference of the densities, and inversely proportional to viscosity.