Preliminary relationships between precision acoustic observations and core geotechnical and chemical properties at contaminated sites

Two major precision acoustic marine surveys have been carried out over the last four years with the USEPA at two contaminated sites. Each site had available extensive geotechnical and chemical core data to allow the establishment of initial statistical relationships between the acoustic data and the core information. Using historical data for expected acoustic response of clean and gas free sediments, it was found that deviations in the acoustic parameters of bottom loss, velocity, and absorption occurred in the contaminated sediments when compared to the expected clean sediment response. Initial results indicated that the deviations in acoustic properties from normal sediments were found to be related to gross gas and contaminate content of these sediments. The initial statistical models relating the acoustic properties to the core data are presented with illustrations of the use of this technique for contaminated sediment distribution mapping. It is critical to note that these relationships appear to be site specific and the success of the program resulted from the proper mix of core and microspaced acoustic survey lines.