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

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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.