“…For those situations where drilling causes problems, some of the needed geologic information may be obtained with a geophysical survey. Surveys of sediment deposits have involved many different geophysical methods, including airborne imagery (Singhroy and Barnett, 1984), airborne elec-tromagnetic profiling (Middleton, 1977), electrical resistivity sounding (Auton, 1992;Crimes and others, 1994;Jacobson, 1955;Middleton, 1977;Saarenketo and Maijala, 1994;Wilcox, 1944), frequency domain electromagnetic profiling (Auton, 1992;Middleton, 1977), P-wave refraction (Crimes and others, 1994;Middleton, 1977;Odum and Miller, 1988;Saarenketo and Maijala, 1994), S-wave refraction (Barnett and Ellefsen, 2000;Ellefsen and Barnett, 2001), and ground-penetrating radar (Jol and others, 1998;Saarenketo and Maijala, 1994). Moreover, electrical resistivity sounding, time domain electromagnetic sounding, frequency domain electromagnetic profiling, and ground-penetrating radar were compared by Ellefsen andothers (1998, 1999) to evaluate their suitability for characterizing sediments used for aggregate.…”