Quantification of Gravitational Mass Wasting and Controls on Submarine Scarp Morphology Along the Roseau Fault, Lesser Antilles

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