Diffusion, Solubility, Bubble Growth, and Gas-Driven Eruptions

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9972937 ZhangGas-driven volcanic and lake eruptions are one of the destructive natural hazards. An eruption is a complex process involving a large system and many component processes. The long-term goal of our investigation is to understand the eruptions and to mitigate the hazards. Following our earlier work in experimental simulations and theoretically modeling of the eruption process, we plan in the next phase of investigation to focus on bubble growth and fragmentation, two key component processes in volcanic eruptions. Bubble growth drives the early stage of an eruption and provides overpressurized gas for the later-stage violent eruption. Fragmentation is a defining point in a volcanic eruption and turns a slow bubbly liquid flow to a violent gas flow carrying magma particles. Experiments will be conducted to study water diffusion in rhyolitic melts, solubility at low pressures, and bubble growth rates. The data will be used to construct water diffusivity and solubility models applicable to a large range of temperature and pressure conditions. Such models and bubble growth data will be used to examine our physical understanding of bubble growth, including the consistency of all input data. A fragmentation criterion will be developed on the basis of maximum stress theory and applied to pyroclastic flows owing to dome collapse (a fragmentation process). It is hoped that these developments will significantly improve our knowledge of volcanic eruptions.