Collaborative Research: Linking 3He/4He with eruptive behavior: A time series analysis of recent Kilauea, Iceland, and La Palma eruptions

合作研究：将 3He/4He 与喷发行为联系起来：对近期基拉韦厄火山、冰岛火山和拉帕尔马火山喷发的时间序列分析

• 批准号: 2232532
• 负责人: Marc-Antoine Longpre
• 金额: $ 7.46万
• 依托单位: CUNY Queens College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-15 至 2026-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232532&HistoricalAwards=false
• 关键词: Collaborative; Research; Linking; 3He; 4He

Approximately 800 million people live in regions that are directly exposed to volcanic hazards, yet eruptions remain difficult to forecast. In some cases, earthquakes and ground swelling have been used to predict imminent volcanic eruptions. In other instances, changes in volcanic gas emissions have been used to infer changes in volcanic activity because gas emissions are thought to be linked to the ascent of magmas beneath volcanoes preceding eruptions. This project explores the possibility that volcanic gas chemistry might hold vital clues about magma recharge that could help forecast the onset and course of volcanic eruptions. Magmas from the deep Earth are rich in 3He (an isotope of helium that is very rare compared to 4He). Thus, magma recharge events may cause increases in 3He relative to 4He (i.e., higher 3He/4He). This hypothesis will be tested by measuring 3He/4He values in lavas from recent eruptions in Hawai’i, Iceland, and the Canary Islands. By comparing 3He/4He to other volcanic indicators, including lava discharge rate, lava composition, earthquake frequency and magnitude, and other chemical features of volcanic gases detected by satellites, the team will attempt to link changes in 3He/4He to volcanic activity. If helium systematics change in response to potentially hazardous volcanic processes, real-time helium monitoring of volcanoes may be justified. Not only does this project aim to broaden our understanding of volcanic systems, it also emphasizes high school, undergraduate, and graduate education. In partnership with the New Heights Charter School, in Brockton Massachusetts, the science team will develop lectures and activities relating to volcanology. Two undergraduate summer student fellows at Woods Hole Oceanographic Institution will be recruited from City University of New York (CUNY), which has a diverse student population. Two additional CUNY undergraduate students will participate by conducting independent study projects. One graduate student enrolled in the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program will contribute to all stages of the research. And this work will provide employment for an autistic woman through a partner organization that facilitates rehabilitation for individuals with disabilities.Volcanic hazard forecasting remains a pressing and elusive challenge for the volcanology community. Seismic activity and ground deformation monitoring are often difficult to link with magmatic processes. Integrative monitoring approaches show the most promise, especially those that supplement established techniques with geochemical monitoring. Helium isotopes show great potential in this regard because they (i) are sensitive to recharge events and (ii) can be monitored—in fumaroles, soils, geothermal waters, and lavas—during eruptions and during periods of repose. Furthermore, previous work indicates that helium isotopes (3He/4He) are sensitive to magma recharge events from the mantle. The goal of this project is to assess the causes of 3He/4He variability on timescales of weeks to months in order to determine whether costly real-time helium isotope monitoring efforts would improve volcanic hazard forecasting. This study will produce magmatic 3He/4He time series records for three recent eruptions: the Lower Eastern Rift Zone of Kīlauea in Hawaii (2018), Fagradalsfjall in Iceland (2021), and Cumbre Vieja in the Canary Islands (2021). Magmatic helium will be extracted from clinopyroxene and olivine mineral separates from lava samples spanning each eruption. Comparison of lava 3He/4He, major and trace element abundances, radiogenic isotopes, and remote sensing data—including ground deformation, seismicity, satellite-based SO2 emissions, and lava discharge rates—will establish whether magma recharge is principally responsible for 3He/4He variability. Alternatively, source heterogeneity or lithospheric helium assimilation might be dominant. By investigating multiple well-monitored eruptions, this project will potentially identify common causes of helium isotopic variability during volcanic eruptions.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.

大约有 8 亿人生活在直接遭受火山灾害的地区，但火山喷发仍然难以预测。在某些情况下，人们利用地震和地面膨胀来预测即将发生的火山喷发。在其他情况下，人们利用火山气体排放的变化来预测。用于推断火山活动的变化，因为气体排放被认为与火山喷发前火山下方岩浆的上升有关。气体化学可能掌握有关岩浆补给的重要线索，有助于预测火山喷发的开始和过程。地球深处的岩浆富含 3He（一种与 4He 相比非常罕见的同位素），因此，岩浆补给事件可能会发生。导致 3He 相对于 4He 增加（即更高的 3He/4He） 该假设将通过测量最近喷发的熔岩中的 3He/4He 值来检验。通过将 3He/4He 与夏威夷、冰岛和加那利群岛的其他火山指标进行比较，包括熔岩排放率、熔岩成分、地震频率和震级以及卫星检测到的火山气体的其他化学特征，研究小组将尝试如果氦气系统因潜在危险的火山过程而发生变化，那么对火山进行实时氦气监测可能是合理的。该项目旨在扩大我们对火山系统的了解，它还强调高中、本科和研究生教育，与马萨诸塞州布罗克顿的新高地特许学校合作，科学团队将开展与火山学相关的两个暑期讲座和活动。伍兹霍尔海洋研究所的学生研究员将从纽约城市大学 (CUNY) 招募，该大学拥有多元化的学生群体，另外两名 CUNY 本科生将通过开展独立研究项目参与其中。技术-伍兹霍尔海洋研究所联合项目将为研究的各个阶段做出贡献，这项工作将通过一个促进残疾人康复的合作组织为一名自闭症妇女提供就业机会。火山灾害预测仍然是一个紧迫而难以捉摸的挑战。地震活动和地面变形监测通常很难与岩浆过程联系起来，特别是那些用地球化学监测补充现有技术的方法在这方面显示出巨大的潜力。因为它们（i）对补给事件敏感，并且（ii）可以在喷发期间和休止期间在喷气孔、土壤、地热水和熔岩中对来自地幔的岩浆补给事件敏感。该项目的目标是在数周至数月的时间尺度上评估 3He/4He 变化的原因，以确定实时成本是否昂贵氦同位素监测工作将改善火山灾害预测。这项研究将生成最近三次火山喷发的岩浆 3He/4He 时间序列记录：夏威夷基拉韦厄东部裂谷带（2018 年）、冰岛 Fagradalsfjall（2021 年）和 Cumbre Vieja。加那利群岛（2021）将从单斜辉石和橄榄石矿物分离物中提取岩浆氦。比较每次喷发的熔岩样品 3He/4He、主量元素和微量元素丰度、放射性同位素和遥感数据（包括地面变形、地震活动、基于卫星的 SO2 排放和熔岩排放率）将确定岩浆是否补给。是造成 3He/4He 变化的主要原因，或者，来源异质性或岩石圈氦同化可能是主导因素。该项目将有可能确定火山喷发期间氦同位素变异的常见原因。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。