“Mud acoustics” and the ocean acoustics program

Shallow water acoustics is one of the major thrusts of the Office of Naval Research Ocean Acoustics Program and has been an important area of interest to Navy programs since at least the work of Pekeris, Ewing, and Worzel in the 1940’s. In the 1950’s and early 1960’s, there was a flurry of activity both in the US and UK focused on propagation within and reflection from the seabed and the acoustical characteristics marine sediments. This work formed the basis of a research program carried out by the applied ocean acoustics branch of the acoustics division at the Naval Research Laboratory in the 1970’s. In April 1991, with the Cold War coming to an end, and a shift in interest from blue water to the littorals, ONR sponsored a workshop on shallow water acoustics at the Woods Hole Oceanographic Institution. This meeting, including underwater acousticians, geologists, geophysicists, and physical oceanographers, largely set the stage for the next 30 years of shallow water acoustics research supported by ONR. Prominent efforts include the ONR Geoclutter Program and the Shallow Water 2006 experiments, both focused on regions dominated by sandy bottoms. This talk describes more recent efforts in regions characterized by muddy bottoms.