Submarine landslides – architecture, controlling factors and environments. A summary.

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Abstract

Submarine landslides are a broad term for indicating the phenomena of failure of near-seabed sediments under the effect of gravity. This occurs with the concomitance of stresses applied to the seabed with the ensuing of environmental conditions that might cause sediment weakening. Submarine landslides are typically classified based on the type of movement that produces them – e.g. slide, slump, creep. Recent studies have also proposed alternative classifications based on the morphology of the resultant deposits (i.e. confined vs frontally emergent failures) and based on the submarine physiographic region from which landslides initiate (i.e. attached vs detached failures).

The overall morphology of landslide deposits reflects the dominant collapse process, with sliding and slumping, for example, generating distinct products. Failures, however, share a typical tripartite architecture with an updip headwall domain, a translational domain and a downslope toe domain, each typified by distinct structures. Carefully examination of these structures can provide evidence – kinematic indicators – which are critical for unravelling the evolution of submarine landslides.

Landslides occur in a variety of submarine environments which are governed by specific natural processes often able to cause slope failure. These factors are referred as to triggering factors, if they act over a short period ultimately causing failure (e.g. earthquakes), or preconditioning factors, if they arise during deposition, and solely favour slope collapse (e.g. stiff vs weak sediments). Statistical studies of submarine landslides from a variety of locations worldwide demonstrate that most occur on gentle slopes, with the largest ones found in seismically quiet regions. These results imply that slope steepness and seismic activity are not the only controls on size and distribution of landslides, but instead the combination of multiple preconditioning and triggering factors might be critical for defining their mode of initiation and emplacement.
Original languageEnglish
Title of host publicationRegional Geology and Tectonics
Subtitle of host publicationVolume 1: Principles of Geologic Analysis
PublisherElsevier
Chapter16
Pages417-439
Edition2nd Edition
ISBN (Print)978-0-444-64134-2
DOIs
Publication statusPublished - 2020

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