Prodigious submarine landslides on the Hawaiian Ridge

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

The extensive area covered by major submarine mass wasting deposits on or near the Hawaiian Ridge has been delimited by systematic mapping of the Hawaiian exclusive economic zone using the side‐looking sonar system GLORIA. These surveys show that slumps and debris avalanche deposits are exposed over about 100,000 km2 of the ridge and adjacent seafloor from Kauai to Hawaii, covering an area more than 5 times the land area of the islands. Some of the individual debris avalanches are more than 200 km long and about 5000 km3 in volume, ranking them among the largest on Earth. The slope failures that produce these deposits begin early in the history of individual volcanoes when they are small submarine seamounts, culminate near the end of subaerial shield building, and apparently continue long after dormancy. Consequently, landslide debris is an important element in the internal structure of the volcanoes. The dynamic behavior of the volcanoes can be modulated by slope failure, and the structural features of the landslides are related to elements of the volcanoes including rift zones and fault systems. The landslides are of two general types, slumps and debris avalanches. The slumps are slow moving, wide (up to 110 km), and thick (about 10 km) with transverse blocky ridges and steep toes. The debris avalanches are fast moving, long (up to 230 km) compared to width, and thinner (0.05–2 km); they commonly have a well‐defined amphitheater at their head and hummocky terrain in the lower part. Oceanic disturbance caused by rapid emplacement of debris avalanches may have produced high‐level wave deposits (such as the 365‐m elevation Hulopoe Gravel on Lanai) that are found on several islands. Most present‐day submarine canyons were originally carved subaerially in the upper parts of debris avalanches. Subaerial canyon cutting was apparently promoted by the recently steepened and stripped slopes of the landslide amphitheaters.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Prodigious submarine landslides on the Hawaiian Ridge
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/JB094iB12p17465
Volume 94
Issue B12
Year Published 1989
Language English
Publisher AGU
Contributing office(s) Pacific Coastal and Marine Science Center
Description 20 p.
First page 17465
Last page 17484
Other Geospatial Hawaiian Ridge