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

当地时间2023年7月10日下午6点左右，位于冰岛西南部的Fagradsfjall火山或更具体地说是Litli HRútu火山喷发。在过去的几个月里，这座火山愈演愈烈。最近的一次活动始于2023年4月雷克雅内半岛西部的地面膨胀，这是火山喷发前的一种常见现象。地面膨胀的速度高达每月约1厘米，表明岩浆正在火山下方15公里深处积聚。在火山中积累的岩浆释放出以水蒸气、二氧化碳和硫磺气体为主的气体。这些气体从深处上升，并通过通风口和表面的裂缝逃逸。Fagradalsfjall火山之前的喷发产生了来自地表以下24公里的熔岩流。该项目的研究人员将在喷发之初和整个喷发过程中收集样本并测量气体，以调查气体来源是否来自地壳和地幔深处。这项工作比较了包括硫和碳在内的气体成分以及碳同位素，以确定岩浆气体的来源和来源的深度。研究人员还将量化每天排放的气体总量。这一结果可以用来评估火山下面可能仍有多少岩浆准备喷发。这项工作还将确定目前正在喷发的岩浆是否来自可能在不久的将来喷发的更深的岩浆。在利特利·胡图尔火山喷发中获得的信息将为其他危险火山也可能发生的过程提供宝贵的见解。该项目将为科学家提供检查目前位于冰岛西南部的Fagradsfjall喷发，或者更具体地说，Litli HRúur喷发的途径。这项请求的目的是收集喷发烟羽的气体样本，并利用无人机测量正在进行的喷发期间的二氧化硫通量和二氧化碳/二氧化硫比率。这些样本将利用新墨西哥大学在冰岛大学使用的仪器进行分析，以获得喷发出的二氧化碳的碳同位素值。获得的数据将为二氧化碳的来源和喷发期间岩浆脱气的动力学提供约束。上一次发生在Fagradsfjall的喷发发生在2021年，它利用了一个位于莫霍面或其下约20公里深的岩浆库。随着喷发的演化，地表喷发的熔岩来自越来越深的地方。目前的喷发可能会以同样的方式进行，并允许从很深的地方采集二氧化碳样本，并迅速转移到地表。这一转移将提供一个独特的机会，以限制冰岛深部地幔的碳同位素组成，并限制再循环碳对冰岛羽流源区的任何贡献。此外，二氧化碳/二氧化硫比值的时间序列数据收集与二氧化硫通量测量相结合，将使研究人员能够计算喷发的二氧化碳通量，并评估在喷发期间有多少岩浆在脱气，以及这些岩浆来自什么深度。正在进行的喷发期间的信息(二氧化碳流量、岩浆脱气深度、参与脱气的岩浆数量和二氧化碳来源)的组合将提供关于这种动态玄武岩喷发的脱气过程的前所未有的细节。由此产生的数据也适用于热点火山的其他玄武岩喷发，如KīLauea，HawaiʻI。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智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.