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

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.