Abstract: 

In the field of volcanology, one significant hurdle to understanding volcanic systems is that we are limited to observations made at the literal surface level during a blink of geologic time, in order to interrogate processes that stretch deep into the earth and into the past. Despite relatively few opportunities to directly observe eruptions, we want to answer questions such as, "How much magma is there? Where will magma reach the surface? When will the next eruption be?” To complement direct observations, volcanologists model volcanic processes using known physics, in order to make predictions about the architecture and behavior of real volcanoes. However, model-based predictions are limited by the assumptions used to construct them. My dissertation seeks to use physics-based models of magma on the move to better constrain real-world magma systems. 

In the first chapter, I model magma traveling through a conduit and erupting as a lava fountain. I use lava fountain heights observed at Sierra Negra Volcano, Galapagos, to constrain H2O and CO2 content, which in turn better constrains the total volume of magma within the shallow chamber at Sierra Negra in concert with more conventional prediction methods, which assume gasless basalt in the chamber. In the second chapter, I challenge the assumption that magma pressure within a dike (a magma-filled crack) has an insignificant effect on the direction in which the dike will propagate. I use a finite element model, which fully couples magma in a reservoir and dike to a hydraulically-fracturing elastic host rock, to quantify the extent to which the dike influences its own path. In the third chapter, I study how melt moves through a vertically extensive mush (crystal matrix with interstitial melt) to recharge shallow reservoirs with application to Axial Seamount, an underwater volcano. I investigate the extent to which depth-variable permeability within the mush is capable of predicting observed inter-eruption uplift at Axial and compare with existing, mush-less interpretations of the system. Taken together, my work uses physics-based models of magma in motion to reinterpret existing predictions made by conventional models, through challenging conventional assumptions.