This project is jointly funded by the Petrology and Geochemistry and the Established Program to Stimulate Competitive Research (EPSCoR) programs. Augustine Volcano in Alaska is one of the most frequently active volcanoes in the US and is considered a very high threat by the U.S. Geological Survey. The hazards posed by a volcano depend on the size and style of an eruption, and many questions remain as to what controls these eruption characteristics at intermediate arc volcanoes like Augustine. For example, are large and explosive eruptions driven by larger volumes of magma supply at shallow depths in the crust, or by faster ascent rates, or both? Prehistoric tephras (named Tephra B and Tephra M) that erupted from Augustine Volcano can provide insight into how eruptive behavior changes through time. This project has as a goal to investigate the links between magma plumbing systems and eruption explosivity. It will target two of the primary factors that determine eruption style: magma composition and the rate at which the magma ascends through the crust. Important societal benefits will emerge from this work, specifically related to volcanic hazards in the US, and that are broadly applicable to other intermediate arc volcanoes globally. Finally, this project initiates new volcano observatory-academic partnerships between the Alaska Volcano Observatory, Colgate University, and Middlebury College. This partnership will accelerate the translation of basic science to applications and monitoring that will provide active research-based curricula at two undergraduate institutions.
The goals of this project are to: 1) use whole rock (pumice), phenocryst, glass, and melt inclusion geochemical data to identify the number, geometry, and relationships between the subsurface magmatic reservoirs that fed the eruptions that produced units Tephra M and Tephra B at Augustine, 2) investigate indicators of magmatic ascent rate such as volatile concentrations, crystal textures, and bubble textures within the erupted material, 3) characterize how volcanic plumbing systems evolve through time by comparing tephras B and M to historic and older prehistoric and Pleistocene deposits, and 4) investigate small-scale variability in eruption style through detailed sampling within the stratigraphy of Tephras M and B, with a targeted effort to characterize both microlite-poor and microlite-rich samples. This will resolve some of the observational bias that exists in Augustine’s record, and will help characterize the potential magnitude and importance of this bias at intermediate arc volcanoes. Data from this project will provide new constraints on the physical and chemical processes that drive ascent and explosivity and determine how magma storage reservoirs evolve over time.
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.
