EAR-PF The Role of Deformation in Triggering Volcanic Eruptions

Ryan, Amy Grace, Orinda CA

Investigators

Abstract

Dr. Amy Ryan has been awarded an NSF EAR Postdoctoral Fellowship to carry out research at the University of Minnesota to determine the role that deformation of magma chambers plays in setting off volcanic eruptions. Supervolcanoes like Yellowstone volcano (USA) are fed by magma chambers that have small pockets of fluid magma distributed within a body of immobile magma “mush, dominated by crystals with magma filling in spaces between. Volcanic eruptions and associated unrest occur when physical forces cause changes in the Earth’s crust and those pockets move through the mush to the surface. Studies of erupted lavas have shown that this movement can occur suddenly, geologically speaking, taking as little as a few months to hundreds of years. However, the physical conditions and processes that allow the fluid magma to move through the stiff, immobile mush are unknown. Dr Ryan’s work includes experiments that recreate conditions beneath supervolcanoes to characterize the geologic processes that drive magma movement beneath volcanoes. The results of Dr. Ryan’s study will provide insight into the conditions that lead to increased volcanic unrest and help those monitoring active volcanoes to create better risk mitigation strategies. The work includes field work in northern Minnesota. Dr. Ryan will partner with the Wolf Ridge Learning Center to develop Next Generation Science Standard (NGSS)-aligned classroom lessons for K-12 students, as well as a series of interactive field guides. Additionally, Dr. Ryan will mentor undergraduates in all aspects of research and the development of educational materials. Dr. Ryan will be conducting high-temperature and high-pressure deformation experiments in a gas-medium, Paterson apparatus. Experimental samples will consist of a disk of glass (“magma”) stacked in series with a disk of a composite (“mush”) composed of crushed glass mixed with fine quartz sand up to a crystal fraction of 80%. Samples will be heated and pressurized then be subjected to pore-pressure gradients, compressed or sheared at rates and magnitudes representative of deformation conditions mushes and magmas experience in natural reservoirs. Following deformation, analyses of samples will include specialized imaging to look for magma infiltration structures and to measure the volume of migrated magma. The major project objectives are to (1) determine the deformational conditions (type, rate and magnitude) that create dilatant regions in the high-viscosity, low-permeability mush that allow for magma infiltration and (2) based on experimental results, identify the multi-scale geologic processes that can feasibly trigger magma infiltration and, as a result, reservoir reorganization. These results will find application in constraining input parameters for numerical models of magma extraction and transport in the upper crust. Research outputs from this project will be disseminated in high-impact, open-access, peer-reviewed articles, conference presentations, public lectures, university-based websites and social media. In addition, the project will also include a field study to compare textures that form in experiments to those that developed in natural intrusive bodies and are preserved in the rock record. Field work will involve the participation of students from local community or tribal colleges. Finally, educational materials will be developed based on the experimental work and field study and be made available for local learning centers and schools. 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.