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Reconstructing the most explosive volcanic eruption this century

Isobel A Yeo1 , Michael A Clare1, Jacob Nash1,2, James Hunt1, Shane Cronin3, Sally Watson4, Richard Wysoczanski4, Sarah Seabrook4, Kevin MacKay4, Marta Ribo5, Jose Borrero6, Rene Vaiomounga7 and Taaniela Kula7

  • Affiliations: 1 Ocean BioGeosciences, National Oceanography Centre, Southampton, UK 2 University of Southampton, Southampton, UK 3 Faculty of Science, University of Auckland, Auckland, New Zealand/Aotearoa 4 National Institute of Water and Atmospheric Research, Wellington, New Zealand/Aotearoa 5 Auckland University of Technology, Auckland, New Zealand/Aotearoa 6 School of Engineering, University of Southern California, USA 7 Ministry of Lands, Survey, Planning and Natural Resources, Kingdom of Tonga

  • Presentation type: Talk [Invited]

  • Presentation time: Thursday 10:30 - 10:45, Room R280

  • Programme No: 2.2.1

  • Theme 2 > Session 2

Abstract

The 2022 eruption of the shallow submarine Hunga Volcano, Kingdom of Tonga, was the most explosive volcanic eruption this century and the first VEI >5 eruption in the satellite era. The eruption generated a devastating tsunami with >20m run-up, and damaged subsea telecommunications cables disconnecting Tonga from the global internet, with many Tongans cut off for more than a year. The eruption sequence and associated subaerial and seafloor change are unusually well constrained, from a combination of pre-eruption remote sensing, seafloor surveys and sampling, fast-response post-eruption seafloor surveys and sediment coring that characterised offshore eruption deposits, land-based surveys of tsunami deposits and damage, and personal testimonies. These collectively provide a unique opportunity to study the deposits and record of volcanic hazards above and below the ocean surface. These data reveal the creation of fast-moving (up to 120 km/hr) submarine volcaniclastic density currents, produced as the eruption column collapsed onto the steep submerged slopes of the volcano, travelling distances > 100 km, depositing up to 40 m of material, and damaging telecommunications cables. Submarine deposits evidence complex flow in all directions. Onshore observations reveal multiple tsunami waves, and evidence of an older tsunami, with the resultant deposits and preservation being strongly controlled by local topography and offshore sediment availability. This eruption provides a rare opportunity to link observed volcanic processes unequivocally to the deposits they produced and provides valuable observations that can aid hazard forecasting and inform interpretation of similar deposits elsewhere and further back in the geological record.