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Probabilistic volcanic hazard and impact assessment of the Auckland Volcanic Field, Aotearoa New Zealand

James H. Williams1 , Josh L. Hayes2, Thomas M. Wilson1, Graham S. Leonard2, Rebecca H. Fitzgerald2, Alana Weir3, Christina Magill2, Mark Bebbington4, Stuart Mead4, Jan Lindsay5, Heather Craig1, Zoë Bowbrick1, Bethany Millar1, Anna Talbot1

  • Affiliations: 1 School of Earth and Environment | Te Kura Aronukurangi, University of Canterbury | Te Whare Wānanga o Waitaha, Private Bag 4800, Ōtautahi | Christchurch, Aotearo 2 GNS Science | Te Pū Ao, Te Awakairangi | Lower Hutt, Aotearoa New Zealand 3Department of Earth Sciences, University of Geneva, Geneva, Switzerland 4 School of Agriculture and Environment | Te Kura Mātauranga mō Ahuwhenua me Te Taiao, Massey University | Te Kunenga Ki Pūrehuroa, Te Papa-i-Oea | Palmerston North, Aotearoa New Zealand 5Te Whare Pūtaiao | Faculty of Science, University of Auckland | Waipapa Taumata Rau, Tāmaki Makaurau | Auckland, Aotearoa New Zealand 

  • Presentation type: Talk [Invited]

  • Presentation time: Friday 08:45 - 09:00, Room S160

  • Programme No: 6.7.2

  • Theme 6 > Session 7

Abstract

Volcanic eruptions can be particularly complex and/or enduring events capable of producing multiple hazards simultaneously and/or consecutively, causing compounding impacts on society. Correspondingly comprehensive volcanic risk assessments are therefore required to inform appropriate disaster risk and resilience strategies. We present a conceptual framework for probabilistic volcanic multi-hazard impact assessments. We develop this framework within a case study of the Auckland Volcanic Field (AVF), Aotearoa New Zealand, utilising existing eruption scenarios. This probabilistic approach will reduce the potential for bias that scenarios inevitably suffer from, and allow easier comparison with other similarly assessed risks (e.g. seismic). We use existing dynamic eruption scenarios for the AVF, which include multiple volcanic hazards and transitions in eruptive style, for which we have relative likelihoods at every location in the field based on the matching of environmental factors and eruption styles. We combine these with detailed location-specific modelling of hazard phenomena to produce pseudo-probabilistic hazard and impact estimates. We present results for site-specific probability of various hazard impacts, including combinations of hazard impacts arising from the entire suite of scenarios, weighted by likelihood of occurrence. The results of this case study will inform short- to long-term planning and mitigative strategies in Tāmaki Makaurau Auckland city, including for nationally significant sectors. The framework and case study will be incorporated as a probabilistic volcanic multi-hazard impact module for broader national volcanic risk assessment and management frameworks.