Laboratory Acoustic Measurements of Continental Shelf Sediments at Low Kilohertz Frequencies and Elevated Pressures

A method is described for measuring the compressional wave velocity and attenuation of seafloor sediments in the laboratory at effective pressures up to 3 MPa in the frequency range 1 kHz to 10 kHz. Copper-jacketed, cylindrical samples of sediment, 40 cm long and 6.8 cm diameter were placed in a long, water-filled, thick-walled, stainless steel tube. The sample causes constructive and destructive interference of the acoustic pulse in the tube, from which the acoustic properties of the sediment can be calculated. Acoustic data for silty-clays from the UK continental shelf are shown to be consistent with published values for in-situ sediments of similar grain sizes.