Close‐range acoustic scattering from mud volcanoes

Submarine mud volcanoes occur in many parts of the world’s oceans and form an aperture for gas (mostly methane) and fluidized mud emission from the earth’s interior. Their characteristics are of considerable interest to the geology, geophysics, geochemistry, and underwater acoustics communities. For the later community, mud volcanoes are important because they pose a potential source of clutter for active sonar. Close‐range (single boundary interaction) scattering measurements from a mud volcano in the Straits of Sicily were conducted with a vertical source and receive array. The data show target strengths from 800–3600 Hz of 6–12 dB for a monostatic geometry with grazing angles of 3–5 degrees. The target strengths are very similar for vertically bi‐static paths with incident grazing angles of 3–5 degrees and scattered angles of 33–45 degrees. The evidence suggests that the scattering mechanism is the mud volcano (carbonate) structure. [Work supported by the Office of Naval Research and NATO Undersea Research Centre.]