Mechanical Modeling of Pre‐Eruptive Magma Propagation Scenarios at Calderas. Issue 3 (24th February 2023)

• Record Type: Journal Article
• Authors: Mantiloni, L.; Rivalta, E.; Davis, T.
• Is Part Of: Journal of geophysical research. Volume 128:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-24
• Subjects: dike propagation -- magma pathways -- stress modeling -- pre‐eruptive scenarios -- calderas; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2022JB025956
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: Simulating magma propagation pathways requires both a well‐calibrated model for the stress state of the volcano and models for dike advance within such a stress field. Here, we establish a framework for calculating computationally efficient and flexible magma propagation scenarios in the presence of caldera structures. We first develop a three‐dimensional (3D) numerical model for the stress state at volcanoes with mild topography, including the stress induced by surface loads and unloading due to the formation of caldera depressions. Then, we introduce a new, simplified 3D model of dike propagation. Such a model captures the complexity of 3D magma trajectories with low running time, and can backtrack dikes from a vent to the magma storage region. We compare the new dike propagation model to a previously published 3D model. Finally, we employ the simplified model to produce shallow dike propagation scenarios for a set of synthetic caldera settings with increasingly complex topographies. The resulting synthetic magma pathways and eruptive vent locations broadly reproduce the variability observed in natural calderas. Plain Language Summary: Understanding the pathways that bring magma from an underground chamber to the surface helps to prepare for future eruptions in volcanic areas. Dikes are fractures filled with magma and represent the most common mechanism of magma transport in the Earth's crust. Their trajectories may be curved if the Earth's crust is deformed by the load of topography or by tectonic forces. Here we first discuss a model of such deformation processes in volcanic regions with complex but mild topography. Then, we develop a simplified dike propagation model that we compare to a more sophisticated one. Next, we combine our models and simulate magma pathways in artificially‐generated scenarios. Key Points: We present numerical models of crustal stress state in the presence of caldera structures We develop a fast dike propagation model and validate it on a previous numerical model We combine our stress and dike models to simulate magma pathways at synthetic calderas