Magma eruptions are fascinating phenomena that have captured the attention of humanity for millennia. They also represent a significant natural hazard. This project is concerned with fundamental questions regarding eruptive systems: Why do some silicic magmas erupt while others stall in the subsurface? Why do some magmas erupt effusively (i.e. as lava flows) while others do so explosively? Are these different magmas that are predestined to different eruptive potential and style, or are they similar magmas subject to different contingencies? Much attention has been given to the importance of external triggers (e.g. earthquakes) in initiating eruptions. Many lines of evidence suggest, however, that eruption triggers are only effective to the extent that a magma body is already primed to the point where eruption is already very likely or inevitable. The fundamental question that this project aims to address is what is the path for priming of a magmatic body? The project will explore the importance of the internal evolution (i.e. crystallization, bubble formation, and magma evolution) of silicic magmas to eruptive potential, and in particular, to explosive potential. A combination of thermodynamic and fluid dynamics modeling will be employed, using selected natural systems as inspiration and guides to exploring the parameter space of the models. While the research being conducted is academic in nature, it will help further the understanding of the eruptive potential of magmatic systems, and may eventually help volcanologists concerned with systems that directly affect society.
As part of this project, a thermodynamic model that can appropriately describe the evolution of high-silica systems will be developed, and it will be coupled with new and existing models of the dynamics of the chamber itself and of its walls. Modeling tools developed under this project will be made available to the scientific community as standalone software, web services, and browser-based web clients that will permit users to apply these tools to their own scientific questions and teaching needs. Natural systems to be studied include the Bishop Tuff (CA), Peach Spring Tuff (AZ-NV-CA), and the Highland Range Volcanics (NV), taking advantage of their unique magmatic and eruptive histories to assess some of the first order controls on the eruptive potential of silicic magmas.
Magma eruptions are fascinating phenomena that have captured the attention of humanity for millennia. They also represent a significant natural hazard. This project is concerned with fundamental questions regarding eruptive systems: Why do some silicic magmas erupt while others stall in the subsurface? What happens to magmas that causes them to begin ascent and violent explosive eruptions? Much attention has been given to the importance of external triggers (e.g. earthquakes) in initiating eruptions. Many lines of evidence suggest, however, that eruption triggers are only effective to the extent that a magma body is already primed to the point where eruption is already very likely or inevitable. The fundamental question that this project aimed to address is what is the path for priming of a magmatic body? The project explored the importance of the internal evolution (i.e. crystallization, bubble formation, and magma evolution) of silicic magmas to eruptive potential, and in particular, to explosive potential. We developed a thermodynamic model to more appropriately describe the evolution of high-silica systems (rhyolite-MELTS). We have also started to develop models that will couple this thermodynamic model with fluid dynamics models to realistically simulate the evolution of magma bodies in the subsurface. The program rhyolite-MELTS is freely available (http://melts.ofm-research.org) The models developed were applied to three natural systems: (1) the Bishop Tuff (CA), (2) the Peach Spring Tuff (SW USA), and (3) the Highland Range Volcanic Sequence (NV). While the research conducted was academic in nature, the models and results may lead to improved understanding of the evolution and eruptive potential of magmatic systems, which eventually could help assess hazards related to volcanic activity.
