IODP Leg 340 Lesser Antilles

加勒比海的小安的列斯群岛拥有大量的火山。虽然蒙特塞拉特是目前唯一正在喷发的火山的所在地，但在过去的一个世纪里，有许多火山喷发，包括一些导致该地区大量死亡的火山喷发。因此，如果我们要向当地居民提供合理的建议，了解火山的喷发历史和这些喷发的地质灾害影响是至关重要的。通过研究陆地上的火山沉积物无法轻易收集到这些信息，因为年轻喷发的产物掩盖了过去事件的证据，而且无论如何，喷发的大部分产物都被迅速输送到海洋中。因此，该地区火山历史的最佳记录来自于分析保存在岛屿周围海洋沉积物中的火山活动记录。此外，该地区的大多数火山都经历了一个巨大的新鲜火山岩圆顶的生长周期，然后变得不稳定并坍塌到海洋中。如果这些坍塌很大，它们有可能产生巨大的海啸，这可能对当地民众构成重大威胁。同样，由于这些崩塌将碎片转移到海洋中，因此在海洋中可以找到它们的大小和形成速度的最佳记录（这对评估它们的潜在危害至关重要）。虽然我们已经能够从传统的研究船只上获得过去几十万年的一些信息，但我们知道，岛上的火山活动已经延续了几百万年，有证据表明，在这段时间里，有更大的火山爆发和圆顶坍塌事件。因此，为了研究这一长期记录，我们需要在海洋沉积物中钻几百米深，并回收沉积物，以便在船上和陆地上的实验室进行研究。为了实现这一目标，我们将乘坐IODP船进行为期7周的巡航，从蒙特塞拉特岛和马提尼克岛附近回收钻芯。

The Lesser Antilles islands in the Caribbean Sea are host to a large number of volcanoes. Although Montserrat is host to the only volcano that is erupting at the present time, there have been many eruptions over the past century, including some that have led to large numbers of fatalities in the region. Hence, an understanding of the eruptive history of the volcanoes and the geohazard implications of these eruptions is critical if we are to provide sound advice to the local population. This information cannot be readily gathered by studying the volcanic deposits on land, because the products of younger eruptions bury the evidence of past events and most of the products of the eruptions are, in any case, rapidly transported to the oceans. Hence, the best record of the volcanic history in the region comes from analysing the record of volcanic activity that is preserved in the marine sediments that surround the islands. In addition, most of the volcanoes in the region go through cycles of growth of a large dome of fresh volcanic rock that then becomes unstable and collapses into the ocean. If these collapses are large, they have the potential to generate large tsunamis that could represent a significant hazard to the local populace. Again, because these collapses transfer debris to the oceans, the best record of their size and speed of formation (which are critical to assessing their hazard potential) is to be found in the oceans. Although we have been able to obtain some information extending back over the past hundred thousand years from conventional research vessels, we know that volcanic activity on the islands has extended back several millions years and there is evidence that there were much larger eruptions and dome collapse events during this time. So, in order to study this long term record we need to drill several hundred metres deep through the marine deposits and recover the sediments for study on board the ship and in our laboratories on land. In order to accomplish this, we will be undertaking a 7 week long cruise aboard the IODP ship to recover drill cores from off the islands of Montserrat and Martinique.