Deterministic and stochastic analyses of acoustic plane-wave reflection from inhomogeneous porous seafloor

Abstract

The propagator matrix technique for the acoustic plane-wave reflection in layered, porous, anisotropic seafloor is combined with Monte Carlo simulation to investigate the layering effect of the sediment. Statistical data from a geologically known site are processed and used as a benchmark. Realizations of sediment property profiles are generated using a spectral technique. A deterministic analysis demonstrates that the amplitude and phase of reflection coefficient is highly dependent on the variation of porosity. In a stochastic analysis, the effect of randomness is examined. It is found that the fluctuation of the sediment physical properties around a mean profile has a significant influence on the seabed reflectivity, particularly for the incident angles near and above the critical value. Frequency behavior of reflectivity is strongly dependent on the correlation length of medium inhomogeneities. This behavior is attributed to the interaction among different waves that propagate in the porous sediment layers, suggesting the possibility of obtaining the properties using the reflection loss data.