RAPID: Sources and Fluxes of CO2 during the 2023 Fagradsfjall Eruption using drone- and ground- based sampling and measurement techniques

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Fagradsfjall Volcano or more specifically Litli Hrútur, located in southwest Iceland erupted on July 10, 2023 at about 6 PM local time. The volcano built up activity over the past few months. The most recent activity began with ground inflation, a common occurrence before eruptions, in April 2023 in the western Reykjanes Peninsula. Ground swelling occurred at rates up to about 1 cm per month and indicated that magma was accumulating at 15 km depth beneath the volcano. Accumulating magma at volcanoes emits gases that are dominated by water vapor, carbon dioxide and sulfur gases. These gases rise from depth and escape through vents and cracks at the surface. Previous eruptions from Fagradalsfjall volcano have produced lava flows that came from up to 24 km below the surface. Researchers on this project will collect samples and measure gases at the beginning and throughout the current eruption to investigate whether the gas sources are from deep in the Earth’s crust and mantle. The work compares gas compositions including sulfur and carbon as well as carbon isotopes to pinpoint the origin of magmatic gas and the depths to its source. Researchers will also quantify the total amount of gases emitted per day. The results can be used to evaluate how much magma may still be beneath the volcano and ready to erupt. The work will also determine whether the currently erupting magma is fed by deeper magma that may erupt in the near future. The information gained at Litli Hrútur eruption will provide valuable insights into processes that may also occur at other hazardous volcanoes. This project will provide access for scientists to examine the current eruption of Fagradsfjall or more specifically Litli Hrútur, located in southwest Iceland. The purpose of this request is to collect gas samples from the eruption plume as well as measure the SO2 flux and CO2/SO2 ratio during the ongoing eruption utilizing UAVs. The samples will be analyzed utilizing an instrument that University of New Mexico has had running in at the University of Iceland to obtain carbon isotope values of the erupting CO2. The data obtained will provide constraints on the sources of CO2 and the dynamics of magma degassing during the eruption. The previous eruption at Fagradsfjall which occurred in 2021 tapped into a magma reservoir that was located at about 20 km depth just at or below the Moho. As the eruption evolved the lavas erupting at the surface were sourced from greater and greater depth. The current eruption may progress in the same manner and allow sampling of CO2 that originates from great depth and is transferred rapidly to the surface. This transfer will provide a unique opportunity to constrain the carbon isotope composition of the deep Icelandic mantle and constrain any contribution of recycled carbon into the Icelandic Plume Source region. In addition, time-series data collection of CO2/SO2 ratios combined with SO2 flux measurements will allow researcher to compute the CO2 flux from the eruption and evaluate how much magma is degassing during the eruption and from what depth this magma is sourced. That combination of information (CO2 flux, magma degassing depth, amount of magma involved in degassing and CO2 source) during the ongoing eruption will provide unprecedented details on the processes of degassing at such a dynamic basaltic eruption. The resulting data has applications to other basaltic eruptions at hot spot volcanoes such as Kīlauea, Hawaiʻi.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.