MAGMA RHEOLOGY and VOLCANIC ERUPTION: Experiments and Models

该研究项目包括火山学中两个不同但互补的主题。1)硅酸盐熔体粘度模型：Redux。粘度是控制岩浆运移和喷发的最重要的物理性质。2008年，我们发表了用于预测天然含水硅酸盐熔体粘度的“GRD模型”。该模型被广泛接受为最好的可用模型，但由于使用该模型的地球科学家的多样性不断增加，第二代模型至关重要。目前的局限性包括：1)该模型没有捕捉到许多流纹岩熔体的低t粘度；ii)我们不考虑溶解的二氧化碳；iii)铁被视为单一物种（即FeO_Total），而硅酸盐熔体同时含有Fe3+和Fe2+；iv)我们没有考虑压力的影响(P)；v)该模型是经验的，这限制了其预测衍生物理化学性质的能力。我建议发布第二代模型来消除这些限制。由此产生的模型将捕获几乎所有在地球和其他行星上发现的硅酸盐熔体，并将为预测其他热化学性质提供更强大的理论基础。2)火山系统岩石力学：实验与模型。岩浆流变学是认识和预测火山喷发类型和强度的关键。火山系统的岩石力学是一个新的、动态的、竞争激烈的研究领域；它位于岩石力学和实验火山学这两个已确立的领域的交汇处。本实验的目的是确定火山喷发条件下火山材料的流变性能。这些数据被用来建立本构方程，预测天然岩浆的流动，作为应力、应变率、温度和晶体含量的函数。这些岩浆流变的本构方程是建立更为复杂和精确的火山喷发模型的关键。

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.