Geoacoustic Study of New Jersey Coast from Townsends Inlet to Hereford Inlet.

Abstract : A comprehensive geoacoustic study has been performed for a 7-mile stretch of coastline off the coast of New Jersey between Townsends Inlet and Hereford Inlet for the purpose of defining the limits of available granular materials. The work was performed in support of the U.S. Army Engineer District, Philadelphia's, feasibility study for shore protection solutions for the Atlantic coast of New Jersey. Specifically, the objective of this investigation was to quantify the bottom and subottom sediments in terms of in situ density, mean grain size, and soil type from the seafloor surface to a depth of about 20 ft below the bottom, where possible, providing initial estimates of the sediment characteristics as related to their potential use as beachfill material. A high-resolution acoustic reflection technique was used to quantitatively assess the characteristics of the naturally occurring marine sediments. Analysis of 3,500-Hz and 1,000-Hz seismic reflection data in conjunction with vibracore sampling data from selected sites throughout the New Jersey coast study area has been completed. The seismic data were correlated with the laboratory analysis of the sample data through acoustic impedance and acoustic absorption analysis. This being a reconnaissance level study, the results are not intended to assess the suitability of any marine sediment as beach quality material; rather the results are intended to pinpoint areas for further detailed investigations.