Seismic, tomographic and oceanographic insights into water mass interactions and sediment stability on the Demerara Plateau

Investigating the origins of large submarine landslides along seismically inactive continental margins is crucial in assessing tsunami risks in coastal regions. In this study, we use a combination of multi-channel seismic, seismic tomographic, oceanographic, expendable bathythermograph and remote sensing data along the eastern Demerara Plateau, located offshore French Guiana and Surinam. We aimed to image the deep-water processes responsible for the repeated landslides originating from a 350 km continuous head-wall scarp located along the plateau. Our comprehensive dataset enables us to expand the spatio-temporal coverage of water column observations, allowing the identification of a strong pycnocline between the Antarctic Intermediate Water and the North Atlantic Deep-Water. We also image a North Brazil Current associated eddy along the Demerara Plateau slopes. Within the seismically inactive context of the plateau, we propose that the interactions between water masses and sedimentary layers may trigger submarine landslides identified along the margin.