DETERMINISTIC AND STOCHASTIC ANALYSES OF ACOUSTIC PLANE-WAVE REFLECTION FROM INHOMOGENEOUS POROUS SEA-FLOOR

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. Statis tical data from a geologically known site are processed and used as a benchmark. Realizations of sediment property profiles are generated us ing a spectral technique. A deterministic analysis demonstrates that t he amplitude and phase of reflection coefficient is highly dependent o n the variation of porosity. In a stochastic analysis, the effect of r andomness is examined. It is found that the fluctuation of the sedimen t physical properties around a mean profile has a significant influenc e on the seabed reflectivity, particularly for the incident angles nea r 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 possibil ity of obtaining the properties using the reflection loss data. (C) 19 96 Acoustical Society of America.