Submarine landslide morphometrics and slope failure dynamics along a mixed carbonate-siliciclastic margin, north-eastern Australia

Puga-Bernabéu, Ángel, López-Cabrera, Javier, Webster, Jody M., and Beaman, Robin J. (2022) Submarine landslide morphometrics and slope failure dynamics along a mixed carbonate-siliciclastic margin, north-eastern Australia. Geomorphology, 403. 108179.

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Abstract

Comparatively little work has been carried out on the morphology and distribution of submarine landslides on mixed carbonate-siliciclastic margins. The morphometric analysis of 84 open slope submarine landslides on the Great Barrier Reef (GBR) margin of north-eastern Australia provides useful insights into slope failure dynamics and frequency distribution of landslides on mixed margins. Our analysis has revealed that the slope area affected by failures (12.6% of the margin) is similar to siliciclastic-dominated passive margins, although the total volume of remobilized sediment (73 km3) is comparatively small. Landslide scars lie at shallower depths to the south of the margin (mean of 576 m vs 1517 m to the north) and there is good correlation between the depth at origin and depth at termination for the GBR landslides. The cumulative frequency distribution of volume, area and total length of the GBR landslides does not fit to common distributions (e.g., power law, logarithmic or exponential) for the entire dataset. Still, the cumulative frequency distribution of landslide dimensions can be statistically explained either by a power law similar to other passive margins, or by a lognormal distribution similar to some siliciclastic margins. Morphometric characteristics, such as the volume of sediment released per unit width and the probability function of volume distribution suggest that slope failures mainly involved relatively unconsolidated sediments. We find that the disintegration by debris flows was the dominant process along the entire GBR margin and that their spreading efficiency and mobility was relatively low. Margin stratigraphy, fluid overpressure at the base of the slope, and detachment surfaces at the boundary between different lithologies that separate sedimentary cycles may have preconditioned the slope to fail. This compilation provides a robust morphometric framework that allows comparison with existing and future slope failure databases, and lays the foundation for performing numerical simulations to assess the landslide-generated tsunamigenic hazards along the GBR margin.

Item ID: 72758
Item Type: Article (Research - C1)
ISSN: 1872-695X
Copyright Information: © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
Date Deposited: 02 Jun 2022 01:59
FoR Codes: 37 EARTH SCIENCES > 3705 Geology > 370504 Marine geoscience @ 100%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180504 Marine biodiversity @ 100%
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