Collaborative Research: ELUCIDATING CONDUIT, ERUPTION AND PYROCLAST TRANSPORT DYNAMICS OF LARGE SILICIC SUBMARINE ERUPTIONS

海底有数以万计的火山。目前尚不清楚其中有多少在任何给定的时间喷发，因为大多数喷发被数百至数千英尺深的水覆盖，防止喷发产物逃逸到大气中或海面上，在那里它们可以被船只、飞机或卫星发现。同样，目前还不知道这些海底火山中有多少会爆发，产生大量的火山灰和浮石，然后通过洋流分布，或者造成火山斜坡不稳定，从而导致海啸。由于海底喷发，特别是那些爆炸性的海底喷发是隐藏在人们视线之外的，我们对它们如何运作、喷发产物及其分布以及它们的地质灾害潜力的了解几乎是未知的。幸运的是，2012年7月，人们发现一只200平方公里的浮石筏漂浮在西太平洋1600米深的哈弗尔火山上方的海洋上，这表明这是一次重大的爆炸性喷发。利用这一事件，该项目对火山喷发进行了重大的科学调查。这项研究涉及对火山、喷发和相关喷发产物及其在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，调查人员将收集样本和沉积物岩芯，并创建该地区的海底照片马赛克。这项研究还涉及高分辨率海底测绘和对火山附近和远离火山地区的相关矿床的地层分析。调查人员将汇编和分析所有可用的摄影图像、喷发前和喷发后的海底地图，以及分析沉积物岩芯和火山灰结构。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。这项研究的一个具体重点是确定挥发物，如H2O、SO2和硫在喷发中所起的作用。这项研究的目标是确定：(1)岩浆上升速度和管道过程的组合导致从1600多米深的水中形成水下喷发烟柱；(2)数据是否能够阐明关于目前陆地上发现的、但来自水下喷发的沉积物中缺乏细灰的悬而未决的争议；以及(3)喷发柱坍塌产生的密度流是质量沉积物从火山流向以外的主要输送机制，还是其他过程占主导地位。这项研究的更广泛的影响包括在研究和最先进的领域和实验室科学技术方面的大量本科培训，以及将所有研究人员和参与机构的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，以及建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。还包括对当地社区团体和K-12学校的介绍，对地质灾害和灾害规划的影响，对EPSCoR州一个机构的支持，以及对科学和工程领域性别比例不足的早期职业调查员的支持。

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.