In the summer of 2005, the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center, mapped more than 321,400 sq. km. of seafloor in the Gulf of Alaska in support of efforts to establish the limits of the juridical continental shelf of the United States as defined under the Law of the Sea Treaty. Both bathymetry and high-resolution backscatter data were collected with a 12-kHz EM120 multibeam echoshounder aboard the University of Hawaii’s R/V Kilo Moana.

In support of efforts to establish an extended continental shelf under the auspices of the Law of the Sea Treaty, the United States and other nations have been collecting high-resolution multibeam sonar data in many previously unmapped regions of the Arctic., The U.S. has conducted eight dedicated mapping cruises since 2003 (four in collaboration with Canada) in the mostly ice-covered waters north of Alaska as far north as 83.5o N (Mayer et al., 2010) using the USCG Icebreaker HEALY equipped with a 12-kHz multibeam sonar.