Collaborative Research: Physical Properties of Bubble- and Crystal-bearing Melts and Their Implications for Eruption Dynamics: Integrated Theoretical, Experimental and Field-based

合作研究：气泡和含晶体熔体的物理性质及其对喷发动力学的影响：综合理论，实验和实地研究&。 过去十年的实地和理论研究表明，岩浆上升的速度在决定随后爆发的风格和暴力方面起着关键作用。这种依赖性是岩浆上升（减压）时所经历的物理变化的结果。 在减压过程中，气泡成核、生长和聚结;晶体也可能成核和生长。气泡和晶体的存在反过来又影响了岩浆的流动能力（流变学），从而影响了岩浆的持续上升。 出于这个原因，开发一个准确的岩浆上升和喷发模型需要我们了解气泡和晶体的分布作为地球表面以下深度的函数，以及气泡和晶体对岩浆流变学的影响。 我们建议通过实验，理论和实地研究相结合来解决这两个问题。 我们的具体目标是：（1）确定悬浮晶体对含气泡熔体流变学的影响;（2）使用火山样本的气泡结构来估计穿过火山管道的剪切（速度）剖面;和（3）检查渗透性（气泡互连性，允许气体逸出）火山碎屑的气泡和晶体含量的函数。

COLLABORATIVE RESEARCH: Physical Properties of Bubble- and Crystal-bearing Melts and their Implications for Eruption Dynamics: Integrated Theoretical, Experimental and Field-based studiesEAR-0207362; EAR-0207471PIs: Cashman&Wallace; Manga Magma must ascend to the Earth's surface prior to erupting. Field and theoretical studies over the past decade have shown that the rate of magma ascent plays a critical role in determining the style, and violence, of the ensuing eruption. This dependence results from physical changes that the magma undergoes as it ascends (decompresses). Bubbles nucleate, grow, and coalesce during decompression; crystals may also nucleate and grow. The presence of bubbles and crystals, in turn, affects the magma's ability to flow (its rheology), and thus its continued ascent. For this reason, development of an accurate model of magma ascent and eruption requires that we understand both the distribution of bubbles and crystals as a function of depth below the Earth's surface and the effect of bubbles and crystals on magma rheology. We propose to address both of these questions through a combination of experimental, theoretical and field-based studies. Our specific goals are: (1) to determine the effect of suspended crystals on the rheology of bubble-bearing melt; (2) to use the bubble structure of volcanic samples to estimate shear (velocity) profiles across volcanic conduits; and (3) to examine the permeability (bubble-interconnectedness that permits gas escape) of volcanic clasts as a function of both their bubble and crystal content.