Quantification of gravitational mass wasting and controls on submarine scarp morphology along the Roseau fault, Lesser Antilles

Type Article
Date 2021-04
Language English
Author(s) Hughes AlexORCID1, Escartín JavierORCID1, 2, Olive Jean‐arthurORCID2, Billant Jeremy3, Deplus Christine1, Feuillet Nathalie1, Leclerc FrédériqueORCID3, Malatesta LucaORCID4
Affiliation(s) 1 : parking decartesUniversité de Paris, Institut de Physique du Globe de Paris, CNRS, F-75005 Paris, France
2 : Laboratoire de Géologie, Ecole Normale Supérieure (CNRS UMR 8538) PSL Research University Paris ,France
3 : Université Côte d'Azur, CNRS Observatoire de la Côte d'Azur, IRD Géoazur Valbonne ,France
4 : GFZ German Research Center for Geosciences Potsdam ,Germany
Source Journal Of Geophysical Research-earth Surface (2169-9003) (American Geophysical Union (AGU)), 2021-04 , Vol. 126 , N. 4 , P. e2020JF005892 (25p.)
DOI 10.1029/2020JF005892
WOS© Times Cited 1
Keyword(s) Lesser Antillies, Mass mass wasting, Normal normal faults, Roseau Faultfault, Submarine submarine landscape evolution, Submarine submarine landslides
Abstract

Due to challenges involved in mapping the seafloor at high‐resolution (e.g., < 2 m), data are lacking to understand processes that control the evolution of submarine normal fault scarps, which cover large parts of the global seafloor. Here, we use data from autonomous deep‐sea vehicles to quantify local erosion and deposition associated with a pronounced tectonic surface scarp formed by slip on the submarine Roseau normal fault (Lesser Antilles). We use high‐resolution video imagery, photomosaics, and high‐resolution bathymetry data (0.1–10 m/pixel) to identify active erosional features on the scarp including channels, steep gullies, small scarps, and debris cones. We compare volumes of erosion and deposition and find that under certain depositional conditions, debris cones effectively record the erosion signal of mass wasting from the footwall with a ratio of hanging wall deposition to footwall erosion of 0.80. We use eroded volumes to estimate earthquake‐induced landslide erosion rates for the Roseau fault of 14–46 m Ma‐1. Assuming mass wasting of the Roseau fault scarp is mostly coseismic, the erosion rates for the Roseau fault imply that submarine earthquake induced mass‐wasting can occur at similar rates to various terrestrial lithological and tectonic settings. We present a process‐based model of submarine scarp degradation via retrogressive erosion in basement lithology where scarps have a gravitational stability threshold height of 20–40 m and a long‐term average slope of 30–40°. More generally, the results presented here may be applicable to develop models of submarine landscape evolution based on degradation of normal fault scarps on the seafloor.

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How to cite 

Hughes Alex, Escartín Javier, Olive Jean‐arthur, Billant Jeremy, Deplus Christine, Feuillet Nathalie, Leclerc Frédérique, Malatesta Luca (2021). Quantification of gravitational mass wasting and controls on submarine scarp morphology along the Roseau fault, Lesser Antilles. Journal Of Geophysical Research-earth Surface, 126(4), e2020JF005892 (25p.). Publisher's official version : https://doi.org/10.1029/2020JF005892 , Open Access version : https://archimer.ifremer.fr/doc/00684/79578/