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 measure d experimental data. Accurate geoacoustic data from the New Jersey She lf AGS site have provided profiles of compressional and shear sound sp eed, attenuation, and density. Along with the detailed bathymetry and CTD data, these profiles are used for input to transmission loss and w ave-number calculations. In order to examine range-dependent effects o f geoacoustic properties and geological structures in this region on a coustic wave propagation, parabolic equation (PE) models are employed for frequencies ranging from 75 to 1200 Hz. Sensitivities to variation s in sediment structure and characteristics are determined to show the ir acoustic influences. Uncertainties in geoacoustic parameters and se nsitivities to required vertical resolution of modeled geoacoustic dat a are displayed. Comparisons of elastic PE simulations illustrate the influence of shear effects. Discussion of sediment layering effects an d range dependence on acoustic propagation are given in connection wit h broadband experimental data. (C) 1995 Acoustical Society of America.