SHALLOW-WATER SEDIMENT LAYER STRUCTURE AND COMPOSITION EFFECTS ON RANGE-DEPENDENT ACOUSTIC PROPAGATION AT THE ATLANTIC GENERATING-STATION (AGS) SITE

Effects of shallow-water sediment layers on acoustic propagation over a broad band of frequencies are examined using simulations and measured experimental data. Accurate geoacoustic data from the New Jersey Shelf AGS site have provided profiles of compressional and shear sound speed, attenuation, and density. Along with the detailed bathymetry and CTD data, these profiles are used for input to transmission loss and wave-number calculations. In order to examine range-dependent effects of geoacoustic properties and geological structures in this region on acoustic wave propagation, parabolic equation (PE) models are employed for frequencies ranging from 75 to 1200 Hz. Sensitivities to variations in sediment structure and characteristics are determined to show their acoustic influences. Uncertainties in geoacoustic parameters and sensitivities to required vertical resolution of modeled geoacoustic data are displayed. Comparisons of elastic PE simulations illustrate the influence of shear effects. Discussion of sediment layering effects and range dependence on acoustic propagation are given in connection with broadband experimental data. (C) 1995 Acoustical Society of America.