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Bridging the Gap Between Magma Conduit Models and Near-Field Ground Deformation Observations

Eliot Eaton, Jurgen Neuberg, Susanna Ebmeier

Abstract

Ground deformation at volcanoes offers critical insights into magma plumbing systems across diverse temporal and spatial scales. Understanding of ascent dynamics within volcanic conduits are crucial for utilising near-field ground deformation as a monitoring tool. This study uses finite-element modelling to simulate magma ascent, examining how model parameters and formulation influence pressure and shear stress along conduit walls. Key factors include conduit geometry, boundary conditions at top and bottom of conduit, magma composition, crystallisation, gas exsolution, and plug formation. Our models clarify how magma conduit conditions, such as pre-explosive pressurisation or magmatic plug formation, can be detected by geodetic methods and define the requirements for effective monitoring. Focusing on magma ascent in silicic volcanoes during lava dome-building eruptions, we explore how ground deformation, combined with seismicity and lava dome growth data, reveals the state of the magma conduit. We also assess the potential of high-resolution InSAR to complement ground-based geodetic techniques like tiltmeters and GPS. Finally, we address the challenges of implementing these methods for routine monitoring, aiming to improve volcanic hazard assessments.