Collaborative Research: Degassing-based constraints on the dynamics of submarine eruptions

动力学（上升速率，质量喷发速率，熔岩流动速率等）海底火山喷发占地球每年火山活动的70%左右，基本上是未知的。这项研究将开发一种基于脱气的“地质速度计”（即，一种确定岩浆从岩浆库移动到其在海底的最终安息地的速度的方法）。 对于大洋中脊玄武岩，这将允许量化地球上最大的火山系统的喷发动力学（即，大洋中脊扩展中心），并帮助评估这些动态如何影响来自巨大大洋中脊系统的碳通量。对海底火山熔岩流熔岩样品的结构和挥发物进行详细的微观分析，并进行一套独特的实验室实验，将用于量化洋中脊玄武岩的脱气和泡化机制和速率。将在这些结果的基础上开发一种“地球速度计”。这个地质速度计将使我们能够了解和测量洋中脊熔岩的流速，为它们提供的喷发的减压速率，以及流动形态（片流与枕状熔岩）如何反映喷发速率。分析的重点是来自美国和加拿大西北海岸胡安德富卡山脊上的轴向火山2011年喷发的样本。将通过沿沿着轴向火山喷发裂缝和流动路径收集的样品的挥发性浓度和囊泡大小分布来分析这次喷发的样品的脱气。一个中心的挑战将是温度，降压率，挥发性物质的浓度和囊泡人口的组合物的联系。因此，将利用天然的、二氧化碳过饱和的大洋中脊玄武岩进行一系列实验室减压和冷却实验，以便为模型计算提供见解和输入参数，从而量化结果。2011年Axial火山的爆发将作为测试案例，用于改进脱气模型，并为将研究结果纳入广泛适用的海底火山系统模型提供工具。 该研究还将通过更严格和定量地评估海底玄武岩二氧化碳脱气的控制措施，帮助改善对碳通量的估计。该研究的更广泛影响包括研究生和本科生的支持，以及调查人员通过已经计划的教师培训研讨会与K-12 STEM教师的接触。 研究还将纳入调查人员教授的课程，数据将通过NSF资助的数据管理设施免费提供给公众。

The dynamics (ascent rate, mass eruption rate, lava flow rate, etc.) of submarine eruptions, which account for roughly 70% of the Earth's annual volcanic activity, are essentially unknown. This research will develop a degassing-based "geospeedometer" (i.e., a method for determining how fast magma moves from its magma chamber to its final resting place on the sea floor). for mid-ocean ridge basalts that will allow quantification of eruption dynamics in Earth's largest volcanic system (i.e., the mid-ocean ridge spreading centers) and help to evaluate how those dynamics impact carbon fluxes from the vast mid-ocean ridge system. A combination of detailed microanalysis of textures and volatiles in lava samples from submarine volcanic lava flows and a unique set of laboratory experiments will be used to quantify the mechanisms and rates of degassing and vesiculation in mid-ocean ridge basalts. A "geospeedometer" will be developed on the basis of those results. This geospeedometer will allow us to understand and measure flow rates of mid-ocean ridge lavas, decompression rates of the eruptions feeding them, and how flow morphologies (sheet flow vs. pillow lava) reflect eruption rate. Analyses will be focused on samples from the well mapped and comprehensively sampled 2011 eruption of Axial Volcano on the Juan de Fuca Ridge off the northwest coast of the US and Canada. Samples from this eruption will be analyzed for degassing via volatile concentrations and vesicle-size distributions of samples collected along the Axial Volcano eruptive fissures and flow paths. A central challenge will be the linking of temerature, depressurization rate, and composition to volatile concentrations and vesicle populations. Thus, a series of laboratory decompression and cooling experiments using natural, CO2-supersaturated, mid-ocean ridge basalts will be undertaken to provide insights and input parameters for model calculations, leading to the quantification of results. the 2011 eruption of Axial Volcano will serve as the test case and be used to refine models of degassing and provide the vehicle for incorporating research reesults into broadly applicable models for submarine volcanic systems. The research will also help improve estimates of carbon flux by evaluating more rigorously and quantitatively the controls on seafloor basalt degassing of CO2. Broader impacts of the research include support of graduate and undergraduate students and engagement of the investigators with K-12 STEM teachers via already plannedteacher training workshops. Research will also be incorporated into courses taught by the investigators and data will be made freely available to the public through NSF-funded data management facilities.