MAGMA RHEOLOGY and VOLCANIC ERUPTION: Experiments and Models

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This research program comprises 2 distinct but complementary themes in volcanology.1) A Model for Silicate Melt Viscosity: Redux. Viscosity is the most important physical property governing transport and eruption of magma. In 2008, we published the "GRD model" for predicting the viscosity of natural hydrous silicate melts. The model is widely accepted as the best available but a second generation model is critical due to the ever-increasing diversity of geoscientists that use the model. The current limitations include: i) the model does not capture the low-T viscosity of many rhyolite melts; ii) we do not account for dissolved CO2; iii) iron is a treated as a single species (i.e. FeO_Total) whereas silicate melts contain both Fe3+ and Fe2+; iv) we do not account for the effects of pressure (P); and v) the model is empirical and this limits its ability to predict derivative physical-chemical properties. I propose to release a second generation model to eliminate these limitations. The resulting model will capture virtually all silicate melts found on Earth and other planets and will have a stronger theoretical basis allowing for prediction of other thermochemical properties.2) Rock Mechanics of Volcanic Systems: Experiments and Models. Magma rheology is key to understanding and predicting the styles and intensities of volcanic eruption. The Rock Mechanics of Volcanic Systems is a new, dynamic, and highly competitive area of research; it lies at the interface between the well-established fields of Rock Mechanics and Experimental Volcanology. The goal of this experimentation is to establish the rheological properties of volcanic materials at the conditions attending volcanic eruption. These data are used to build constitutive equations that predict the flow of natural magmas as a function of stress, strain-rate, temperature and crystal content. These constitutive equations for magma rheology are the key to more sophisticated and accurate modelling of volcanic eruptions.