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Experimental constraints on the magmatic parameters controlling the 2022 eruption of Hunga Tonga-Hunga Ha\'apai Volcano, Tonga

Enrico Califano1,2, Silvio Mollo2, Marco Brenna1, Alessio Pontesilli3, Patricia Marks4, Dennis Eul4, Marcus Nowak4, Shane Cronin5, Piergiorgio Scarlato3

  • Affiliations: 1 Department of Geology, University of Otago, Dunedin, New Zealand; 2 Department of Earth Sciences, Sapienza University of Rome, Rome, Italy; 3 Section of Roma 1, National Institute of Geophysics and Volcanology, Rome, Italy; 4 Department of Geosciences, Eberhard Karls University Tübingen, Tübingen, Germany; 5 School of Environment, University of Auckland, Auckland, New Zealand 

  • Presentation type: Poster

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

  • Poster Board Number: 42

  • Programme No: 1.7.29

  • Theme 1 > Session 7

Abstract

The Hunga Tonga-Hunga Ha'apai volcano, located in the Kingdom of Tonga in the Pacific Ocean northeast of New Zealand, is part of the Tonga-Kermadec subduction zone and is renowned for its 2022 eruption, the most explosive volcanic event globally in the past century. This cataclysmic eruption generated acoustic waves that circled the Earth's atmosphere multiple times, propelled a volcanic plume into the mesosphere, and triggered a tsunami that swept across the Pacific Ocean, eventually reaching the coast of South America. In this study, we experimentally investigate the key physicochemical parameters driving the volcanic eruptions at Hunga by comparing the compositions of natural melts and minerals with those produced at the laboratory scale. Isothermal-isobaric crystallization experiments were conducted in a non-end-loaded piston cylinder apparatus and in an internally heated argon pressure vessel. The starting material is a basaltic andesitic lava from the older edifice eruptions, representative of the most primitive products at Hunga. The experimental conditions ranged from 200--300 MPa, 1000--1130 °C, and redox states between 0.5 and 3.5 log units above the quartz-fayalite-magnetite buffer, with H2Omelt varying between 0.6 and 6.4 wt.% to simulate both fluid-absent and fluid-present crystallization scenarios. The mineral assemblage consists of titanomagnetite, clinopyroxene, plagioclase and orthopyroxene, with major oxides and components (diopside-hedenbergite-enstatite and anorthite-albite) closely matching those of natural crystals. The compositions of residual glasses reflect the basaltic andesite to dacite evolutionary trends within the Hunga's plumbing system, offering crucial insights into the pre-eruptive conditions of the magmas that fed the cataclysmic 2022 eruption.