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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 93, NO. B5, PAGES 4279–4299, 1988

The giant submarine Alika debris slide, Mauna Loa, Hawaii

Peter W. Lipman

U.S. Geological Survey, Federal Center, Denver, Colorado


William R. Normark

U.S. Geological Survey, Menlo Park, California


James G. Moore

U.S. Geological Survey, Menlo Park, California


John B. Wilson

Institute of Oceanographic Sciences, Wormley, Godalming, Surrey, United Kingdom


Christina E. Gutmacher

U.S. Geological Survey, Menlo Park, California


Abstract

A 4000-km2 area of submarine slump and slide deposits along the west flank of Mauna Loa volcano has been mapped with GLORIA side-scan sonar images, seismic reflection profiles, and new bathymetry. The youngest deposits are two debris avalanche lobes that travelled from their breakaway area near the present shoreline as much as 100 km into the Hawaiian Deep at water depths of 4800 m. The two lobes partly overlap and together are designated the Alika slide. They were derived from the same source area and probably formed in rapid succession. Distinction hummocky topography, marginal levees, and other features on lower slopes (0.3°–0.6°) of these deposits resemble subaerial volcanic debris avalanche deposits such as 1980 Mount St. Helens and suggest high emplacement velocities. The breakaway area for the Alika slide (10°–15° slopes) is characterized by large block slumps, bounded by normal faults, that probably represent multiple subsidence events before, during, and after the debris avalanches. Lower slopes of the slide contain distinctive lobate-terraced deposits that are interpreted as having been emplaced more slowly, prior to the debris avalanches. Estimated thicknesses of 50–200 m suggest volumes of 200–600 km3 for the two lobes. The combined volume of the entire slide and slump terrane is probably 1500–2000 km3. The slide deposits predate a 13-ka coral reef and probably postdate the block-faulted Ninole Basalt, roughly dated as a few hundred thousand years old. The Alika slide, or a similar deposit recognized on GLORIA images durther north along the Hawaiian Ridge, probably triggered a giant wave that washed 325 m high on Lanai at about 100 ka. Slumping on Mauna Loa has been most intense adjacent to the large arcuate bend in its southwest rift zone, as the rift zone migrated westward away from the growing Kilauea volcano. Slumping events were probably triggered by seismic activity accompanying dike injection along the rift zone. Such massive slumps, landslides, and distal submarine turbidity flows appear to be widespread on the flanks of Hawaiian volcanoes.

Index Terms: 3045 Marine Geology and Geophysics: Seafloor morphology and bottom photography; 8499 Volcanology: General or miscellaneous; 8429 Volcanology: Lava rheology and morphology; 9355 Information Related to Geographic Region: Pacific Ocean.

Citation: Lipman, P. W., W. R. Normark, J. G. Moore, J. B. Wilson, and C. E. Gutmacher (1988), The giant submarine Alika debris slide, Mauna Loa, Hawaii, J. Geophys. Res., 93(B5), 4279–4299.