The Lesser Antilles arc is a mixed siliciclastic and carbonate active margin made of active volcanic and flat Plio-Quaternary carbonate islands. It was built as a result of a complex tectonic history at the slowly converging boundary between the American plates and the Caribbean plate. The sedimentary processes as a consequence of external forcing (earthquakes, volcanism, hurricanes) were rarely documented in such environment and are poorly understood. We exploited an exceptional dataset of high-resolution marine seafloor data acquired during the last 20 years in the northern part of the Lesser Antilles forearc to document the sediment-transport processes. We achieved a detailed morpho-sedimentary study from multi-beam bathymetry, backscattering, and seismic profiles. Two areas could be characterized: 1) the “Rough Area”, along Barbuda to Guadeloupe carbonated islands, characterized by steep (up to 25°) slopes incised by short canyons, and deep basins controlled by major normal faults; 2) the “Channelized Area”, south of Guadeloupe and bordered by active volcanic islands and carbonate platforms, characterized by gentle slopes incised by long canyons. During sea-level high-stands, the sediment seems exported from the carbonate platform by hurricanes or density cascading but appears to settle at the shelf-edge and canyon heads. During sea-level low-stands, a connection may exist between onshore and offshore systems. However, this sediment supply appears not sufficient to generate canyon formation, likely shaped by regressive processes. Shelf breaks of the carbonate banks, platforms and submarine slopes are affected by sediment failures. Some may be associated to voluminous remobilizations and large mass transport deposits. Large earthquakes are likely the main processes in this area to remobilize sediments toward the deep forearc basins by triggering both slope failures and flushing of the canyon heads.

小安的列斯群岛弧是由活跃的火山岩和平坦的Plio-第四纪碳酸盐岛组成的硅质碎屑岩和碳酸盐岩混合活动边缘。它是由于在美国板块和加勒比板块之间逐渐收敛的边界上复杂的构造历史而建造的。由于外部强迫（地震，火山作用，飓风）而造成的沉积过程在这种环境中鲜有记载，人们对此知之甚少。我们利用近二十年来在小安的列斯群岛前臂北部获取的高分辨率海洋海底数据的特殊数据集来记录沉积物的输送过程。我们通过多波束测深，后向散射和地震剖面进行了详细的形态沉积研究。可以表征两个区域：1）“粗糙区域”，沿着巴布达到瓜德罗普岛的碳酸盐岛，特征是由短峡谷切入的陡峭（最高25°）斜坡和受主要正断层控制的深盆；2）瓜德罗普岛以南的“海峡区”，以活跃的火山岛和碳酸盐台地为边界，其特征是由长峡谷切割出的缓坡。在海平面高位期间，沉积物似乎是由于飓风或密度级联从碳酸盐岩平台中排出的，但似乎沉积在了陆架边缘和峡谷顶部。在海平面低位期间，陆上和海上系统之间可能存在连接。但是，这种沉积物的供应似乎不足以形成峡谷，这可能是由回归过程形成的。碳酸盐岩岸，平台和海底斜坡的架子破裂受沉积物破坏的影响。其中一些可能与大量的运输和大量的运输沉积物有关。大地震可能是该地区触发斜坡失稳和冲刷峡谷顶盖的主要过程，将沉积物运往前臂深部盆地。