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Rapid geochemical and petrologic monitoring of Kīlauea's recent eruptions

Elisabeth Gallant1,2, Kendra J. Lynn3, Steve Lundblad1, Kamalani Poepoe1,2, Lichen Forster1, Namy Barnett2, Julie M. Chang2, Annika Dechert4, Meghann Decker1, Natalia I. Deligne3, Drew Downs3, Cheryl A. Gansecki1, Paige A. Johnson1, Nanako Kohagura1, Baylee McDade1,2, Peter Mills5, Abigail R. Nalesnik6, Heather Winslow3

  • Affiliations: 1Department of Geology, University of Hawai'i at Hilo, Hilo, HI, USA 2Hawaiian Volcano Observatory, Hilo, HI, USA 3USGS Hawaiian Volcano Observatory, Hilo, HI, USA 4Department of Earth Sciences, University of Oregon, Eugene, OR, USA 5Department of Anthropology, University of Hawai'i at Hilo, Hilo, HI, USA 6Department of Earth Sciences, University of Delaware, Newark, DE, USA

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 233

  • Programme No: 1.6.11

  • Theme 1 > Session 6

Abstract

The University of Hawaiʻi at Hilo and the USGS Hawaiian Volcano Observatory collaborate in geochemical monitoring during Island of Hawai'i eruptions using energy-dispersive X-ray fluorescence (EDXRF) to analyze whole-rock geochemistry. These data provide information for hazard determination and risk assessment in near real time; analyses are often conducted on the same day as sample collection. These efforts track compositional changes and provide estimates of lava temperatures. Here we present the results from the eight eruptions of Kīlauea since the summit caldera collapse in 2018. Analysis of the six summit eruptions suggests that, the bulk composition of the shallow magma reservoir has become slightly more primitive. Whole-rock MgO was higher in 2020 compared to the 2018 compositions, and MgO has increased almost 1 wt% over 2020-2025. EDXRF analyses also indicate that the lava erupted in June 2024 from the Southwest Rift Zone had accumulated olivine, while the September 2024 middle East Rift Zone eruption is chemically similar to past eruptive events in the area. Petrological studies of olivine and other mineral phases provide additional context for changes since 2018. Olivine macrocrysts from summit eruptions include three populations that are distinguishable by their compositions, zoning patterns, and textures which indicate storage for crystal cargo at 3--5 km depth (South Caldera reservoir), 1--2 km depth (Halema'uma'u reservoir), and from within the post-2018 lava lake. Collectively, these efforts provide important and timely information about the dynamic nature of Kīlauea's frequent eruptions and changes in the system since 2018.