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Explosions in the Sky: Seismo-acoustic and crowdsourced observations of the 2022 eruption of Hunga volcano from across Aotearoa New Zealand

Oliver Lamb 1, Mary Anne Clive2, Rachel Lawson2, Sally Potter2, Geoff Kilgour1, Paul A. Jarvis3, Sara Harrison3, Brad Scott1, Danielle Charlton2

  • Affiliations: 1Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, 3384, New Zealand; 2Te Pū Ao | GNS Science, Auckland Research Centre, Auckland, 1010, New Zealand; 3Te Pū Ao | GNS Science, Avalon Campus, Lower Hutt, 5010, New Zealand

  • Presentation type: Talk

  • Presentation time: Thursday 15:45 - 16:00, Room R280

  • Programme No: 2.1.1

  • Theme 2 > Session 1

Abstract

On 15 January 2022, Hunga volcano (Kingdom of Tonga) underwent one of the largest volcanic eruptions in recent history, generating long-range audible sounds that were reported across the world, including the length of Aotearoa New Zealand. This presented a rare opportunity to document and analyse the long-range propagation of audible volcanic acoustics from both geophysical and social perspectives. Public observations were obtained from a crowdsourced survey to understand the spatial and temporal distribution of eruption sound observed across the country. The results of the survey complemented a dense seismo-acoustic record, including data from microphones, barometers, seismometers, and strong-motion accelerometers. Over 1700 members of the public reported hearing multiple "booming" noises over a 2-hr period on 15 January 2022, perceiving a "light" or "moderate" loudness (proportional to 60 -- 80 dB). Manual analysis of seismo-acoustic data in the North Island found >140 events across two distinct wavepackets within the same 2-hr period, of which 7 had amplitudes >60 dB. Detailed analysis of the seismo-acoustic data clearly recorded two southward-propagating acoustic wavepackets. The first coincided with a Lamb wave generated by the eruption but the second propagated at a slower apparent velocity (~270 m/s) and was likely associated with an extremely rare Pekeris wave. This presentation highlights how crowdsourced data can engage the wider public in volcanology, how joint analysis with geophysical data is shedding new light on a historic eruption, and how such multi-disciplinary studies may be used to understand future volcanic activity.