NERC-NSTC: Erosion in the deep ocean - the impact of the Kuroshio Current on the continental shelf and slope of Taiwan

全球洋流的传送带是地球气候系统的重要组成部分，在全球海洋周围输送热量和营养物质。它们还输送大量的沉积物，并将它们重新沉积在深海的大型漂浮物中。这些沉积物然后提供了一个重要的档案，记录了产生它们的当前系统，以及不断变化的温度和环境条件。近年来，我们越来越认识到，墨西哥湾流等地球表面大洋流中的大尺度涡流也在深海中发挥着重要作用。这些涡流相当于大气中的气旋，集中在海洋锋面，在某些情况下会对海床造成深达数百米的侵蚀。黑潮是这些重要的表层水流系统之一(与锋面有关)，是太平洋海洋循环系统的基本组成部分。我们最近在台湾以南和日本近海的工作表明，这是一个高度动态的系统，它与活动边缘(两个构造板块碰撞的地方)的复杂海底相互作用，深度侵蚀和重新分配沉积物。在这个项目中，我们旨在了解台湾近海黑潮的影响。我们将使用地震反射数据、多波束测深数据(证明了高分辨率海底地图)和岩心样本，以了解洋流对一些地区的影响。我们将具体测试洋流如何与升高的构造脊相互作用，以及它是否能够侵蚀横跨大陆架和斜坡的深水道。然后，我们将调查与这种深度侵蚀相关的危险，包括从板块边界清除沉积物是否会改变该地区的应力状态，可能会对地震强度和频率产生影响--这是以前从未测试过的--以及洋流是否会破坏大陆斜坡的稳定，导致水下山体滑坡和海啸。该项目还将使我们能够在我们在英国、德国和台湾的机构之间建立新的长期合作伙伴关系，以在未来扩大这项工作。对黑潮海流的研究相对较少，但它是了解洋流对大陆边缘的影响，并解决海洋与对人类人口有重大影响的地球深部过程之间的联系的根本新问题的理想自然实验室。

The global 'conveyor belt' of ocean currents are an important part of Earth's climate system, transporting heat and nutrients around the global oceans. They also transport large volumes of sediments and re-deposit these in large drifts in the deep oceans. These sediments then provide an important archive of the current systems that produced them, as well as changing temperatures and environmental conditions. In recent years, we have increasingly recognized that the large-scale eddies in the Earth's large surface currents, such as the Gulf Stream, also play an important role in the deep ocean. These eddies, which are equivalent to cyclones in the atmosphere, are concentrated at ocean fronts, and can cause deep erosion of the seabed - many hundreds of metres deep in some cases.The Kuroshio Current is one of these important surface current systems (associated with a front), that is a fundamental part of the ocean circulation system of the Pacific. Our recent work to the south of Taiwan, and offshore Japan, shows that this is a highly dynamic system which interacts with the complex seabed at an active margin (where two tectonic plates are colliding), deeply eroding and re-distributing sediment.In this project, we aim to understand the effect of the Kuroshio Current offshore Taiwan. We will use seismic reflection data, multibeam bathymetry data (proving high-resolution seabed maps) and core samples, to understand the impact of the current in a number of areas. We will specifically test how the current interacts with elevated tectonic ridges and whether it is capable of eroding deep channels across the continental shelf and slope. We will then investigate hazards associated with this deep erosion, including whether the removal of sediment from the plate boundary changes the stress state in the area, potentially with implications for earthquake magnitude and frequency - something that has never previously been tested - and whether the current destabilizes the continental slope, leading to underwater landslides and tsunamis. This project will also allow us to develop a new, long-term partnerships between our institutions in the UK, Germany and Taiwan, to expand this work in the future. The Kuroshio Current is relatively understudied but it is the ideal natural laboratory to understand the impact of ocean currents on continental margins, and address fundamental new questions about the links between the oceans and deep earth processes that have a major impact on human populations.