NOAA Ship Okeanos Explorer
is outfitted with one of the very few deep water multibeam sonars capable of collecting water column backscatter data. In 2009, the ship unexpectedly imaged a large plume of methane gas seeping into the water column at Mendocino Ridge off the coast of California, using her multibeam sonar. Partnering with the Bureau of Ocean Energy Management (BOEM) and the University of New Hampshire CCOM, a 2011 expedition in the Gulf of Mexico
was conducted to follow-up on this capability, with the primary purpose of studying the feasibility of using this ability to map gases in the water column. With its increased swath width, the multibeam sonar offers the possibility of greatly increasing the seep survey efficiency. In addition to detection and localization, the sonars on the Okeanos Explorer
were assessed for their ability to provide information regarding the seep morphologies, general makeup, and relative densities.