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Insights into Surface Deformation Patterns During Volcanic Unrest

Kyriaki Drymoni 1,2,3, Társilo Girona2, Paul Lundgren1, Jackie E. Kendrick3, Yan Lavallée3

  • Affiliations:  1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA; 2Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK, USA; 3Department of Earth and Environmental Science, Ludwig-Maximilians-Universität München, München, Germany 

  • Presentation type: Poster

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

  • Poster Board Number: 194

  • Programme No: 1.8.25

  • Theme 1 > Session 8

Abstract

Several subsurface processes associated with the storage and transport of magma and/or supercritical fluids contribute to surface deformation at active volcanoes. The complexity of these processes complicates the interpretation of the unrest mechanism (e.g., magma vs. hydrothermal vs. tectonic) and deciphering the subsurface conditions from monitored signals presents a further challenge. Here, we explore various processes that likely occur in the shallow subsurface during volcanic unrest, either individually or in combination, and analyze their relative contribution to surface deformation through physics-based numerical modeling. We designed time-dependent Finite Element Method (FEM) numerical models to investigate how the elastic deformation of the shallow crust produced by a pressurized magma chamber compares to that caused by thermo-mechanical expansion and poroelastic effects due to the flow of supercritical CO2 and H2O. Our models show that magma chamber pressurization, thermal expansion, and poroelasticity can significantly impact ground deformation. These effects vary based on the source depth, crustal properties and timescales. On short timescales (days) in homogeneous segments, a 0.2 MPa increase in magma chamber pressurization causes twice the surface deformation compared to an equivalent magma chamber pressure rise due to poroelasticity. The thermal expansion associated with 10 °C increase leads to ten times more cumulative deformation than short-term magma pressurization, and over longer periods (1-5 years), thermal expansion can be significant. This research provides valuable insights into subsurface processes and improves volcanic unrest signal interpretation, aiding in better forecasting and community safety.