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Characterizing pre- and syn-eruptive processes at Great Sitkin Volcano, Alaska, by integrating seismic data assimilation and satellite-based thermal anomalies

Kyungmin Kim 1, Társilo Girona1, Kyle Anderson2, John Power3, Xiaotao Yang4, Matt Haney3

  • Affiliations: 1Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA; 2California Volcano Observatory, United States Geological Survey, Moffett Field, CA, USA; 3Alaska Volcano Observatory, United States Geological Survey, Anchorage, AK, USA; 4Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA

  • Presentation type: Poster

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

  • Poster Board Number: 273

  • Programme No: 2.4.44

  • Theme 2 > Session 4

Abstract

A deeper understanding of the state of unrest at active volcanoes can be achieved by combining robust physical models with multidisciplinary observations. For instance, the leaky gas pocket model (Girona et al., 2019) connects seismic long-period (LP) and tremor waveforms to key physical parameters that influence volcanic unrest, while subtle thermal anomalies may provide insights into the transport of fluids in the shallow subsurface (Girona et al., 2021). Here, we integrate the leaky gas pocket model into a data assimilation framework to investigate the LP activity associated with the ongoing dome-building eruption of Great Sitkin Volcano, Alaska, which began in 2021. Specifically, using a Bayesian Markov Chain Monte Carlo approach, we provide initial parameter estimates, while a genetic algorithm--based data assimilation method tracks parameter evolution over time. Preliminary results indicate a shallow conduit permeability of around 10-7 m2 prior to the explosive May 25, 2021, eruption, decreasing to 10-12-10-7 m2 during the initial effusive eruption in July 2021. We are also analyzing the spatiotemporal distribution of subtle thermal anomalies using Moderate Resolution Imaging Spectroradiometer (MODIS) data to gain a more detailed understanding of very shallow subsurface conditions. By integrating subtle thermal anomalies into our seismic data assimilation framework, we aim to better identify the conditions leading to dome-building eruptions, elucidate the parameters governing explosive-to-effusive transitions, and refine our understanding of the pre- and syn-eruptive processes at Great Sitkin Volcano.