Collaborative Research: Monitoring hydrothermal fluids, crustal permeability and seafloor morphology in preparation for the next volcanic eruption at the East Pacific Rise, 9'50"N

东太平洋隆起（EPR）是位于东太平洋的一个快速扩张的洋中脊。它是环绕地球的山脊系统的一部分，地壳是由更深的地幔融化物侵入和随之而来的火山喷发形成的。当海水流经海洋地壳时，MOR的热液喷口形成了富含金属的烟囱和柱状排放物。这些热液过程改变了海洋岩石圈和全球海洋的组成，并为化学合成生态系统中的极端生命形式提供了独特的栖息地。了解地下流动模式与地壳条件之间的耦合关系对海洋中脊的所有领域以及相关的地球化学和地球物理研究都具有重要意义。本项目研究的重点是未来几年（~ 2020-2023年）在北纬9°50°的EPR轴可能发生一次新的岩浆事件，涉及喷发或浅层岩浆侵位。这一预测是基于观察到的喷口流体温度的升高和化学趋势。海上科学家将使用研究潜水器Alvin和/或远程操作车辆（ROV） Jason在连续三年的三次巡航中部署仪器并收集喷口流体样本，以研究这些过程。该项目还涉及来自美国和挪威的年轻研究人员之间的合作，这将有助于加强两国研究人员之间的国际联系。研究人员还将通过在斯克里普斯海洋学研究所举行的三次研讨会，为圣地亚哥联合学区制作新的教材。与圣地亚哥县教育办公室的合作将加强他们的环境素养倡议，并帮助为加州和全国的初中和/或高中教师创建下一代科学标准、活动和资源。该项目的研究目标集中在未来几年（~ 2020-2023年），在北纬9°50°地区的EPR轴可能发生新的岩浆事件，无论是喷发还是浅堤就位。这一预测是基于热液喷口流体温度的升高和在热液喷口测量的化学趋势。预计这一事件的形成与地壳动力学的变化有关，这些变化可以在多个热液喷口及其流体对潮汐强迫的地球化学性质和热响应中观察到。具体来说，热响应与加载信号之间的相位滞后和幅度比可以用来跟踪下一次火山喷发的准备阶段。为了监测岩浆补给与其对热液流动的影响之间的关系，该项目将采用数值方法利用自记录高温记录仪获得的出口流体温度记录中观测到的潮汐变化。这一分析结果将约束地壳的孔隙弹性特性。为了实现这些目标，该项目将在三次连续巡航中收集几个相关数据集，每次巡航间隔约1年，每年进行7次Alvin或Jason ROV潜水。数据集包括：(1)每隔15分钟记录一次的出口流体温度记录；Ii)使用等压气密取样器从每个仪器通风口采集年度流体样本；Iii)由系泊传感器记录的潮汐压力和水流强度数据；iv)测量的喷口结构的高分辨率静止和4k分辨率视频图像，以及v)将于2019年12月使用自主水下航行器Sentry获取的基线近底测深和侧扫描数据集。这些数据将成为支撑EPR 9°50'N海洋中脊社区的地球物理学家、生物学家和化学家工作的关键资源。火山喷发。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The East Pacific Rise (EPR) is a fast-spreading mid-ocean ridge located in the eastern Pacific Ocean. It is part of a globe-encircling system of ridges where the crust of the Earth is created by the intrusion of melt from the deeper mantle and consequent volcanic eruptions. Hydrothermal vents from the MOR form chimneys and columns of metal-rich emissions as seawater flows through the oceanic crust. These hydrothermal processes alter the composition of oceanic lithosphere and the global ocean, and provide unique habitats for extreme forms of life in chemosynthetic ecosystems. Understanding the coupling between sub-surface flow patterns and crustal conditions is fundamentally important for virtually all fields of mid-ocean ridge and related geochemical and geophysical research. This research project focuses on the idea that a new magmatic event involving an eruption or shallow magma emplacement, is likely to happen at the EPR axis in the 9°50’N area in the next few years (~2020–2023). This forecast is based on observed increases in vent exit-fluid temperature, and chemical trends. The scientists at sea will employ the research submersible Alvin and/or remotely operated vehicle (ROV) Jason to deploy instruments and collect vent fluid samples during three cruises over three successive years to study these processes. The project also involves a collaboration between young investigators from the USA and Norway that will help strengthen international ties between researchers in both countries. The researchers will also create new teaching materials for the San Diego Unified School district via three workshops held at Scripps Institution of Oceanography. This collaboration with the San Diego County Office of Education will enhance their Environmental Literacy Initiative, and help to create a Next Generation Science Standards,activities and resources for middle and/or high school teachers in California and nation-wide.This project's research objective focuses on the idea that a new magmatic event, either an eruption or shallow dike emplacement, is likely to happen at the EPR axis in the 9°50’N area in the next few years (~2020–2023). This forecast is based on increases in vent exit-fluid temperature and chemical trends measured at hydrothermal vents. The build-up to this event is anticipated to be associated with changes in crustal dynamics that can be observed in the geochemical properties and thermal response to tidal forcing across multiple hydrothermal vents and their fluids. Specifically, the phase lag and amplitude ratio between the thermal response and loading signal can be used to track the run-up to the next volcanic eruption. In order to monitor the relationship between magma resupply and its impact on hydrothermal fluid flow, the project will apply numerical methods to exploit the tidal variability observed in exit-fluid temperature records acquired using self-recording high-temperature loggers. The result of this analysis will constrain poroelastic properties of the crust. To accomplish these goals, the project will collect several correlative datasets on three successive cruises spaced approximately 1-year apart, with seven Alvin or Jason ROV dives each year. The datasets include i) vent exit-fluid temperature records logged at ~15 min intervals; ii) annual fluid samples from each instrumented vent using isobaric gas-tight samplers; iii) tidal pressure and current strength data logged by moored sensors; iv) high-resolution still and 4k-resolution video imagery of vent structures that are instrumented, and v) baseline near-bottom bathymetry and sidescan dataset to be acquired in December 2019 using autonomous underwater vehicle Sentry. These data will be a key resource to underpin the work of geophysicists, biologists and chemists from across the mid-ocean ridge community working at EPR 9°50’N. eruption.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.