Geomorphic and tectonic controls on the location of eruptive centers in the Andean magmatic arc of southern Chile

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Local tectonic stresses associated with the evolution of volcanic edifices may influence shallow magma trajectories and the spatiotemporal evolution of eruptive centers and fissure systems. Physics-based modelling tools are capable of forecasting such magma pathways, but due to sparse field and geochronological data these models often remain poorly constrained and cannot be validated in volcanic systems with a complex history and architecture. There is an urgent need to better understand the evolution of crustal stresses in volcanic edifices on a variety of timescales beyond decadal-scale instrumental observations, which would significantly improve such models. We seek funding to assess the influence of erosion, sedimentation, and tectonics on the evolution of the local stress field within and below volcanic edifices. On millennial timescales, we will investigate magma pathways and eruptive patterns at the Laguna del Maule and the Puyehue-Cordón Caulle of southern Chile that constitute end-member scenarios in the context of depositional loading and erosional unloading, respectively. We will merge geological, geomorphic, and synthetic observations to test the hypothesis that the effects of climate-driven surface processes may interact with tectonism by causing changes in loading stresses at volcanic centers and influencing magmatic dike propagation. This will involve the generation and analysis of high-resolution digital topography derived from aerial photography and satellite images structural and geomorphic field mapping, and geochronology of young volcanic deposits (40Ar/39Ar dating). These insights will be used to constrain analogue experiments of magma propagation and further test and develop the MagmaPropagator tool to derive a general, yet spatiotemporally realistic model of evolving volcanic processes. We expect that the project will ultimately reveal previously unexplored links between volcanism, climate-driven erosion and sedimentation, but also aid in forecasting the spatial characteristics of eruptive centers.