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Deforming Volcanoes with Trans-Crustal Magmatic Systems: The Influence of Magma-Mush Heterogeneity

^^ James Hickey^^ 1, Rami Alshembari1, Lorenzo Mantiloni1, Brendan McCormick Kilbride2, Karen Pascal3, 4, & Fabian B. Wadsworth5

  • Affiliations:  1 Department of Earth and Environmental Sciences, University of Exeter, UK; 2 Department of Earth and Environmental Sciences, University of Manchester, UK; 3 Montserrat Volcano Observatory (MVO), Montserrat; 4 Seismic Research Centre (SRC), University of the West Indies, Trinidad and Tobago; 5 Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Germany.

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 39

  • Programme No: 2.3.25

  • Theme 2 > Session 3

Abstract

Volcano deformation is a key observable to indicate volcanic unrest, conduct hazard assessments, and help forecast possible eruptions. Current volcano deformation models used to interpret deformation observations are overly simplistic; they assume static incompressible fluid-filled magmatic sources and do not account for dynamic natural processes, thus contributing to uncertainty in hazard assessments and eruption forecasts. However, magma exists in heterogeneous, vertically extensive, trans-crustal magmatic systems, variably consisting of interstitial melt contained within a porous crystal-framework, or "mush" zone. Here, we explore the influence of melt and mush heterogeneity on surface deformation during magma resupply. Our physics-based finite element models couple solid and fluid mechanics to simulate mechanical interaction between melt-filled domains, poroelastic mush zones, and solid host rocks, building on recently benchmarked solutions. Preliminary results for a spherical magma reservoir consisting of a melt-filled region overlaying a poroelastic mush indicate that: (1) initiation of surface deformation may lag the beginning of melt resupply by 1-2 years; (2) surface deformation can accelerate even after melt supply has stopped; and (3) surface deformation can continue for ~8 years after melt supply ends. These results contrast with current general understandings of volcano deformation which would typically assume ground inflation starts, and rates are highest, concurrent with magma resupply. Subsequent investigations will further explore the parameter space to understand how pervasive the temporal surface deformation patterns in the preliminary results are. Where possible, results are further illustrated with application to ongoing volcano deformation at Soufrière Hills Volcano, Montserrat.