Mass wasting along the Hawaiian Ridge: giant debris avalanches

Abstract

GLORIA long-range sidescan sonar surveys along the Hawaiian Ridge were undertaken between 1986 and 1991 as part of the United States Geological Survey (USGS) programme to map the seafloor within the entire US 200-mile Exclusive Economic Zone (EEZ). The surveys revealed many irregularly speckled lobes of high acoustic backscatter on the submarine flanks and adjacent seafloor of virtually all the islands and shoals. Coincident with these speckled areas, 3.5 kHz profiles showed the topography to be irregular, with local highs frequently reaching hundreds of metres above the surrounding seafloor.