Physical Properties of Bubble- and Crystal-Bearing Melts and their Implications for Eruption Dynamics: Theoretical, Experimental and Field-Based Studies

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Inside volcanoes, the formation of bubbles (vesiculation), the breaking of magma into discrete pieces (fragmentation), and the loss of gas in bubbles from ascending magma (degassing) are the key processes that control the dynamics of the erupting magma. The ultimate goal of this project is to understand how these processes interact and are reflected in the features of a volcanic eruption and the products it produces.It is proposed to perform experimental and numerical studies of eruption dynamics and modeling of eruption products in order to understand what controls whether an eruption will be explosive or effusive. The research tasks will include measurements of volatile contents and gradients in obsidian from both explosive and effusive eruption to determine the timescales for vesiculation, degassing and fragmentation. In addition, the team will develop conduit models to understand the competing and interacting effects of flow, degassing, and changes in magma rheology. It is planned to continue experimental studies of the effects of bubbles and crystals or the rheology of suspensions to allow for better models of rheology to be included in conduit flow simulations.This project provides graduate training for three students, supports international collaboration, and interaction with a new user facility at the Advanced Light Source. Because the project is aimed at understanding the controls on eruption style and the relationship between conduit processes and features of erupted materials (texture, volatile content), results will provide a better basis for estimating volcanic hazard, both from a modeling perspective, and from measurements on historic and prehistoric deposits.