Morphological signature of the March 2008 swell event on Caribbean beaches

极端海浪往往对沉积海岸线产生最剧烈的影响，因为它们超过了正常的沉积阈值，到达通常不受海浪影响的地区，并携带着原本稳定的物质。极端的海浪很少发生，但往往对沿海地区的行为有几十年甚至几个世纪的主要影响。它们可以由不同的过程生成。众所周知，与飓风和海啸有关的波浪和涌浪对加勒比海和墨西哥湾的海岸线造成了巨大影响。该地区每年发生几次飓风，每年都有一些岛屿受到影响。然而，它们对任何地点的影响取决于它们相对于特定海岸的路径。虽然它们可能是毁灭性的，但它们的影响往往是相当局部的。因此，在任何给定的岛屿上，它们都是相对罕见的。加勒比海啸也有相当局部的影响；它们不像印度洋或太平洋那样具有大规模的影响力。相比之下，大的涌浪是由遥远的风暴产生的，当它们从起源点辐射时，会扩散到大片地区。因此，在许多加勒比岛屿海岸线上，它们比飓风和海啸发生得更频繁，坊间证据表明，它们对海滩侵蚀和增生有重要影响。2008年3月，从圭亚那到波多黎各的整个西加勒比地区的观测者都注意到了一次大涌浪事件的影响。在英属维尔京群岛，珊瑚被从珊瑚礁上扯下来，扔到内陆或沉积在海滩上；在裸露的海岸，海滩后退了30多米，而在隐蔽的海岸，海浪似乎把沙子推到了岸上。本研究项目旨在调查和记录这一事件对英属维尔京群岛周围的影响，从而直接评估加勒比海岛屿上的巨浪事件的形态影响。

Extreme waves often produce the most dramatic impacts on depositional shorelines because they exceed normal sedimentary thresholds, reaching areas that are often above the influence of waves and transporting material that is otherwise stable. Extreme waves occur infrequently but often have the dominant influenec on coastal behaviour over several decades or even centuries. They can be generated by different processes. Waves and surges associated with hurricanes and tsunami are well known for their dramatic impact on coastlines of the Caribbean and Gulf of Mexico. Several hurricanes occur in the region annually and every year some islands are affected. However, their impact at any location depends on their path relative to a particular coast. While they can be devastating, their impacts are often quite localised. Thus on any given island they are a relatively infrequent occurrence. Caribbean tsunami too, have a quite localised influence; they do not have the large scale influence of those in the indian Ocean or Pacific. Large swell waves, in contrast, are generated by distant storms and spread over a large area as they radiate from their point of origin. They are consequently a more frequent occurrence on many Caribbean island shorelines than hurricanes and tsunamis and anecdotal evidence suggests them to have an important influence on beach erosion and accretion. The impact of a large swell event in March 2008 was noted by observers throughout the western Caribbean from Guyana to Puerto Rico. In the British Virgin Islands coral was ripped from reefs and thrown inland or deposited on beaches; on exposed coasts beaches retreated by over 30m while on sheltered coasts the waves appeared to push sand onshore. This research project aims to investigate and record the impacts of this event around the British Virgin Islands and to thereby assess directly, the morphological effect of a swell wave event on Caribbean islands.