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.

中文翻译：

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碳酸盐台地斜坡上的海底滑坡：机械地层的正演数值模拟和破坏前提的情景

碳酸盐岩台地海底斜坡普遍存在边坡破坏和滑坡。它们代表了地层演化的关键组成部分和主要的地质灾害。在大巴哈马银行 (GBB) 平台的西部斜坡和边缘发现了几个第四纪斜坡破坏和大规模运输复合体。本研究评估了与这些事件相关的先决条件的几个假设，与平台的地层和环境历史有关。前向地层模拟器 Dionisos Flow™ 允许根据最近 1.7 Myr 的静海和环境历史，在高时间分辨率的 2D 平台到盆地剖面上重建斜坡地层演化。流体力学模拟器A2应用在这个高分辨率地层网格上，用于计算截面的力学地层，即时空孔隙压力和应力状态分布。冰川低位期间台地边缘的模拟前提条件是两个因素共同作用的结果：来自出现的台地横向流体流动产生的瞬时超压和台地的陡峭地层趋势。在高沉降速率下或由于海平面下降期间静水梯度变化的结果，不会产生显着的孔隙流体超压。在这个二维模拟中没有达到较低斜坡的前提条件，水平应力分布抵消了超压积聚的影响。