Submarine landslides on a carbonate platform slope : forward numerical modelling of mechanical stratigraphy and scenarios of failure precondition
DANQUIGNY, Charles
Centre scientifique et Technique Jean Feger [CSTJF]
Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes [EMMAH]
Centre scientifique et Technique Jean Feger [CSTJF]
Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes [EMMAH]
BORGOMANO, Jean
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement [CEREGE]
Institut Pythéas [OSU PYTHEAS]
Institut de Recherche pour le Développement [IRD]
< Réduire
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement [CEREGE]
Institut Pythéas [OSU PYTHEAS]
Institut de Recherche pour le Développement [IRD]
Langue
EN
Article de revue
Ce document a été publié dans
Landslides. 2021-02, vol. 18, n° 2, p. 595-618
Résumé en anglais
Slope failure and landslides are widespread on the submarine slopes of carbonate platforms. They represent a key component of their stratigraphic evolution and a major geohazard. Several Quaternary slope failures and mass ...Lire la suite >
Slope failure and landslides are widespread on the submarine slopes of carbonate platforms. They represent a key component of their stratigraphic evolution and a major geohazard. Several Quaternary slope failures and mass transport complexes were identified on the western slope and margin of the Great Bahama Bank (GBB) platform. This study evaluates several hypotheses for the preconditions associated to these events, in relation with the stratigraphic and environmental history of the platform. The forward stratigraphic simulator Dionisos Flow™ allows the slope stratigraphic evolution to be reconstructed on a 2D platform-to-basin section at high temporal resolution according to the eustatic and environmental history of the last 1.7 Myr. The hydromechanical simulator A2 is applied on this high-resolution stratigraphic grid for computing the mechanical stratigraphy of the section, that is the spatiotemporal pore pressure and stress state distribution. The simulated precondition of the platform margin during glacial lowstands results from the combination of two factors: transient overpressure generation by lateral fluid flow from the emerged platform and the steepening stratigraphic trend of the platform. No significant pore fluid overpressure is generated under high sedimentation rates or as a result of shift in hydrostatic gradient during sea-level falls. Precondition in the lower slope is not achieved in this 2D simulation, with the horizontal stress distribution counteracting the effect of overpressure build-up. It is found that cemented levels in the lower slope succession do not represent a significant preconditioning factor.< Réduire
Mots clés en anglais
Submarine landslides
Carbonate slope
Pore fluid overpressure
Failure precondition
Forward modelling
Mechanical stratigraphy
Lateral fluid flow