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Investigating conditions for gas-driven volcanic eruptions based on Whakaari Volcano, New Zealand

Sophie Pearson-Grant1 , John Albright2, Jonas Köpping3, Charles Williams1, Craig Miller4, Thomas Driesner3, Patricia Gregg2

  • Affiliations: 1GNS Science, Lower Hutt, New Zealand; 2Department of Earth Science & Environmental Change, University of Illinois at Urbana-Champaign, Urbana, USA; 3Department of Earth and Planetary Sciences, ETH Zürich, Zürich, Switzerland; 4Wairakei Research Centre, GNS Science, Taupo, New Zealand

  • Presentation type: Poster

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

  • Poster Board Number: 72

  • Programme No: 3.14.6

  • Theme 3 > Session 14

Abstract

Gas-driven eruptions are one of the most common types of volcanic eruption in New Zealand and are notoriously difficult to forecast. Forecasting efforts can benefit from holistic, model-driven approaches that investigate a system's evolution and physical state prior to eruption, particularly when combined with multiple types of monitoring data. Our approach is built on two key components: a forward model that explores potential pre-eruptive conditions, and an inversion technique that can find which conditions best fit observed monitoring data. Using this workflow, we have developed heat and fluid flow models and coupled them with degassing and deformation data. Firstly, we investigated rates of heat and fluid flow from magma to the surface in 2D using CSMP++ software. We then used Waiwera software to explore near-surface (< 2 km depth) 3D permeability and heat flow conditions associated with pressure build-up. These models show that reduced permeability within a volcanic edifice, likely due to hydrothermal mineralisation, is a key factor for overpressure that could lead to a gas-driven eruption. Our next step is assimilating gas flux, ground temperature, and deformation data from Whakaari Volcano into coupled Waiwera-PyLith models using the Ensemble Kalman Filter (EnKF). This uses an evolving Monte Carlo suite to investigate how changes in hydrologic conditions and magma-derived fluid flow rates change the system's pressure, temperature, and stress state and the associated monitoring signals. This process will provide insights into volcano-hydrothermal systems prior to gas-driven eruptions, and has potential as a monitoring tool to aid holistic interpretation of monitoring data.