Collaborative Research: Elucidating Conduit, Eruption, and Pyroclast Transport Dynamics of Large Silicic Submarine Eruptions

合作研究：阐明大型硅质海底喷发的管道、喷发和火山碎屑输送动力学

• 批准号: 1357216
• 负责人: Samuel Soule
• 金额: $ 27.87万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2019-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1357216&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Conduit; Eruption

There are tens of thousands of volcanoes on the ocean floor. It is not known how many of these are erupting at any given time because most are overlain by many hundreds to thousands of feet of water that prevent the escape of eruption products into the atmosphere or onto the sea surface where they can be spotted by ships, airplanes, or satellites. Similarly, it is not known how many of these undersea volcanoes erupt explosively, generating large quantities of ash and pumice that is then distributed by currents or cause volcanic slope instabilities that can result in tsunamis. Because seafloor eruptions, in particular those that are explosive in nature, are hidden from view, our knowledge of how they operate, their eruption products and their distribution, and their geohazard potential is almost unknown. Luckily in July 2012, a 200 square kilometer raft of pumice was spotted floating on the ocean in the western Pacific just above Havre Volcano which is under 1600 meters of water, indicating a major explosive eruption. Taking advantage of this event, this project mounts a major scientific investigation of the eruption. The research involves a comprehensive physical and chemical study of the volcano, the eruption, and the associated eruption products and their distribution near and far from their point of origin. Through an oceanographic cruise using state-of-the-art robotic vehicles, the investigators will collect samples and sediment cores and create seafloor photo mosaics of the area. The research also involves high resolution seafloor mapping and stratigraphic analysis of the related deposits in the vicinity of the volcano and in areas extending away from it. Investigators will compile and analyze all available photographic images, pre- and post-eruptive seafloor maps, as well as analyze sediment cores and ash textures. The project also includes analysis and interpretation of stratigraphic, geochemical, and other associated datasets. A specific focus of the research is determining the role that volatiles such as H2O, SO2, and sulfur played in the eruption. Goals of the research are to determine: (1) what combination of magma ascent rates and conduit processes caused the formation of a subaerial eruption plume from water depths of more than 1600 m; (2) if the data can shed light on the outstanding controversy regarding the lack of fine ash in deposits now found on land but that were derived from subaqueous eruptions; and (3) whether density currents that result from eruption column collapse are the primary transport mechanism for mass sediment flux away from the volcano or if other processes dominate. Broader impacts of the research include significant undergraduate training in research and state of the art field and laboratory scientific techniques, as well as cross training and video presentations that will link together all of the researchers and students at the institutions involved. Additional impacts include international collaboration with New Zealand scientists and the creation of a new, international body to study submarine volcanoes and the impacts of their explosive eruption. Also included are presentations to local community groups and K-12 schools, impacts for geohazards and disaster planning, support of an institution in an EPSCoR state, and support of an early career investigator whose gender is under-represented in the sciences and engineering.

海底有数万座火山。目前尚不清楚其中有多少火山正在喷发，因为大多数火山都被数百至数千英尺的水覆盖，从而阻止喷发产物逃逸到大气中或被船只发现的海面，飞机，或者卫星。同样，我们也不知道有多少座海底火山爆发性喷发，产生大量火山灰和浮石，然后通过水流分布或导致火山坡不稳定，从而导致海啸。由于海底喷发，特别是那些本质上具有爆炸性的喷发，是看不见的，因此我们对它们的运作方式、喷发产物及其分布以及潜在的地质灾害的了解几乎是未知的。幸运的是，2012年7月，在西太平洋的哈弗尔火山上方的海洋上发现了一个200平方公里的浮石筏，该浮石筏位于水深1600米以下，这表明发生了一次大规模的爆炸性喷发。利用这一事件，该项目对火山喷发进行了重大的科学调查。该研究涉及对火山、喷发以及相关喷发产物及其在距其起源点附近和远处的分布进行全面的物理和化学研究。 通过使用最先进的机器人车辆进行海洋巡航，研究人员将收集样本和沉积岩芯，并创建该地区的海底马赛克照片。 该研究还涉及对火山附近和远离火山的地区的相关矿床进行高分辨率海底测绘和地层分析。 研究人员将编译和分析所有可用的摄影图像、喷发前和喷发后的海底地图，并分析沉积物核心和火山灰纹理。该项目还包括对地层、地球化学和其他相关数据集的分析和解释。该研究的一个具体重点是确定 H2O、SO2 和硫等挥发物在喷发中所起的作用。研究的目标是确定：(1) 岩浆上升速率和管道过程的组合导致了水深超过 1600 米的地面喷发羽流的形成； (2) 这些数据是否可以阐明关于目前在陆地上发现的、但源自水下喷发的沉积物中缺乏细灰的悬而未决的争议； (3) 喷发柱塌陷引起的密度流是否是大量沉积物远离火山的主要输送机制，或者是否有其他过程占主导地位。 该研究的更广泛影响包括在研究和最先进领域以及实验室科学技术方面的重要本科生培训，以及将相关机构的所有研究人员和学生联系在一起的交叉培训和视频演示。 其他影响包括与新西兰科学家的国际合作以及成立一个新的国际机构来研究海底火山及其爆炸性喷发的影响。还包括向当地社区团体和 K-12 学校进行的演示、对地质灾害和灾害规划的影响、对 EPSCoR 州机构的支持，以及对性别在科学和工程领域代表性不足的早期职业调查员的支持。