The use of a towed, direct-current, electrical resistivity array for the classification of marine sediments

Abstract

Model studies indicate that the DC electric resistivity technique is feasible for sediment classification and layer structuring. A prototype array was built to test the hypothesis that such a technique can be used in an underway mode in the marine environment. A 60-m, inverted array was towed both on and off the seafloor with electrode spacings appropriate for a penetration depth of 10 m below the seafloor. Three different bottom types, namely mud, gassy mud, and sand, were surveyed in the Mississippi Sound using the array. Ground truth was provided with an acoustic seafloor classification system, CTD (conductivity, temperature, and depth) casts, and numerous sediment cores. Data were analyzed using SUBVERT, an inversion routine adapted for an IBM-PC AT.<>