Understanding Dike Propagation Through Comparison of High-fidelity Coupled Fracture and Fluid Flow Models and Field Observations

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Prior to volcanic eruptions magma rises through the crust, most commonly within narrow fractures known as “dikes.” Dike ascent is often accompanied by small earthquakes and deformation of the ground surface which can be detected by ground-based, and in some cases space-based sensors. Not all dikes lead to eruptions; in some cases, they stall and the magma solidifies without erupting. To properly interpret seismic and deformation signals and provide societally-relevant eruption warnings, we must understand the physical and chemical processes that control how rapidly dikes ascend, the paths they take, and whether or not they make it to the surface. These processes include resistance and motion of the solid rock outside the dike, the flow of magma within the dike, fracture of the crust at the dike tip, and possible solidification of the magma as it cools during its journey toward the surface - all of which are interdependent. Segall, Lew, and their team will use sophisticated computational techniques together with ground deformation and earthquake data to model dike ascent in Hawaii, and to develop guidelines for using such data to forecast eruptions in Hawaii and at similar volcanoes worldwide. This research will address one of the Grand Challenges in the National Academies ERUPT report to advance physics-based eruption forecasting. Accurate, high-fidelity models of dike propagation are key to understanding precursors to many eruptions and will ultimately facilitate forecasting at volcano observatories worldwide.This project will leverage advances in computational methods that allow the numerical grid to adapt to the changing shape of the dike as it grows. These and other advances will allow them to address: the conditions (magma viscosity, background temperature gradient, reservoir pressure, volume, and compressibility) that permit a dike to reach the earth's surface; the time-dependent surface deformations and seismicity-inducing stress perturbations that could be used in physics-based eruption forecasting; and the factors that determine whether deep dikes are focused toward or bypass crustal reservoirs. Computed dike ascent histories and predicted surface deformation will be compared to observations of deformation and seismicity that precedes some eruptions, as well as with laboratory analog experiments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.