Development and mass movement processes of the north-eastern Storegga Slide
Development and mass movement processes of the north-eastern Storegga Slide
复制标题
东北部斯托雷加滑坡的发展和群众运动过程
DOI：
10.1016/j.quascirev.2008.09.026
复制
发表时间：
2009
影响因子：
4
通讯作者：
D. Stow
中科院分区：
文献类型：
--
作者：
A. Micallef;D. Masson;C. Berndt;D. Stow
斯托尔加滑坡发生在大约8100年前，是世界上最大、研究最充分的海底滑坡之一。在这项研究中，我们使用新的地貌学技术来约束形成东北斯托加滑坡的海底块体运动，了解不同形式的破坏之间的联系，并提出该地区的修订开发模型。根据这一模型，斯托尔加滑坡的东北部经历了四次大的发育。第一个事件（事件1）在1500 - 2000米的水深触发。在这次事件中，地表沉积物被泥石流和浊流带走，沉积在挪威海盆地。由泥石流和浊流调动的沉积物对海床的负荷导致了疏散结构的发展。与此疏散结构相关的支撑丧失、旧井壁的重新激活和地震荷载激活了事件1的破坏面向主井壁的扩散（事件2）。在一些地区，扩展块体经历了高位移和改造。部分扩张形态和下面的沉积物被大量的泥石流和浊流变形或移走（事件3）。我们认为，扩展块体的高位移和重塑，以及它们被泥石流和浊度流移走，受到孔隙压力增加的影响，可能是由于天然气水合物溶解/解离，或者是由于古滑坡疤痕中等长岩漂移沉积的侧向变化。第四个事件是大规模的块状泥石流，在扩张区南部造成局部压缩和压迫剪切。
The Storegga Slide, which occurred ∼8100 years ago, is one of the world's largest and best studied exposed submarine landslides. In this study we use novel geomorphometric techniques to constrain the submarine mass movements that have shaped the north-eastern Storegga Slide, understand the link between different forms of failure, and propose a revised development model for this region. According to this model, the north-eastern part of the Storegga Slide has developed in four major events. The first event (event 1) was triggered in water depths of 1500–2000m. In this event, the surface sediments were removed by debris flows and turbidity currents, and deposited in the Norwegian Sea Basin. Loading of the seabed by sediments mobilised by the debris flows and turbidity currents resulted in the development of an evacuation structure. Loss of support associated with this evacuation structure, reactivation of old headwalls and seismic loading activated spreading in the failure surface of event 1 up to the main headwall (event 2). In some areas, spreading blocks have undergone high displacement and remoulding. Parts of the spreading morphology and the underlying sediment have been deformed or removed by numerous debris flows and turbidity currents (event 3). We suggest that the higher displacement and remoulding of the spreading blocks, and their removal by debris flows and turbidity currents, was influenced by increased pore pressures, possibly due to gas hydrate dissolution/dissociation or by lateral variability in the deposition of contourite drifts in palaoeslide scars. The fourth event entailed a large, blocky debris flow that caused localised compression and transpressive shearing in the southern part of the spreading area.