Search USGS⌕ Search
Home/Archive/USGS

USGS · 70016446

Large landslides from oceanic volcanoes

R. T. Holcomb·R. C. Searle
View original source ↗Export metadata ↓

Abstract

Large landslides are ubiquitous around the submarine flanks of Hawaiian volcanoes, and GLORIA has also revealed large landslides offshore from Tristan da Cunha and El Hierro. On both of the latter islands, steep flanks formerly attributed to tilting or marine erosion have been reinterpreted as landslide headwalls mantled by younger lava flows. These landslides occur in a wide range of settings and probably represent only a small sample from a large population. They may explain the large volumes of archipelagic aprons and the stellate shapes of many oceanic volcanoes. Large landslides and associated tsunamis pose hazards to many islands. -from Authors

Explore related subjects

Marine GeotechnologyArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R. T. Holcomb, R. C. Searle. 1991. Large landslides from oceanic volcanoes. https://doi.org/10.1080/10641199109379880

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2008

Active diapirism and slope steepening, northern Gulf of Mexico continental slope

Large diapiric and nondiapiric masses of Jurassic salt and Tertiary shale underlie the northern Gulf of Mexico continental slope and adjacent outer continental shelf. Local steepening of the sea floor in response to the vertical growth of these structures is a serious concern to those involved in the site selection and the construction of future oil and gas production and transportation facilities in this frontier petroleum province. The evidence given in this paper supports the conclusion that the present continental slope region of the northern Gulf of Mexico is undergoing active diapirism and consequent slope steepening. Because most of the sediment on the flanks of diapiric structures consists of underconsolidated muds, slumping will take place regularly in response to further diapiric movement.-from Authors

Marine Geotechnology↗
USGS1992

A statistical overview of mass movement characteristics on the North American Atlantic outer continental margin

An analysis of 179 mass movements on the North American Atlantic continental slope and upper rise shows that slope failures have occurred throughout the geographic extent of the outer margin. Although the slope failures show no striking affinity for a particular depth as an origination level, there is a broad, primary mode centered at about 900 m. The resulting slides terminate at almost all depths and have a primary mode at 1100 m, but the slope/rise boundary (at 2200 m) also is an important mode. Slope failures have occurred at declivities ranging from 1° to 30° (typically, 4°); the resultant mass movement deposits vary in width from 0.2 to 50 km (typically, 1–2 km) and in length from 0.3 to 380 km (typically, 2–4 km), and they have been reported to be as thick as 650 m. On a numeric basis, mass movements are slightly more prevalent on open slopes than in other physiographic settings, and both translational and rotational failure surfaces are common. The typical mass movement is disintegrative in nature. Open slope slides tend to occur at lower slope angles and are larger than canyon slides. Further, large‐scale slides rather than small‐scale slides tend to originate on gentle slopes (≍ 3–4°). Rotational slope failures appear to have a slightly greater chance of occurring in canyons, but there is no analogous bias associated with translational failures. Similarly, disintegrative slides seem more likely to be associated with rotational slope failures than translational ones and are longer than their nondisintegrative counterparts. The occurrence of such a variety of mass movements at low declivities implies that a regional failure mechanism has prevailed. We suggest that earthquakes or, perhaps in some areas, gas hydrates are the most likely cause of the slope failures.

Marine Geotechnology↗