Flow and fragmentation of melts and magmas: developing a unified view through experimental, numerical and field investigations.

世界上百分之十的人口（即几亿人）居住在距离活火山100公里的范围内。此外，随着全球人口的增加和对自然资源需求的增长，这一数字将会上升。当火山爆发时，它们的表现可能是热情洋溢的、爆炸性的，或者两者兼而有之。喷发活动产生熔岩流和有毒气体，而爆炸活动则涉及岩浆的破裂（碎裂），分散熔融液滴，当碎裂有效时，致命的火山灰云/流可以传播数公里。因此，喷发方式（喷涌式还是爆发性）直接控制着危害的类型、空间足迹和程度，从而对人口构成风险。因此，确立活动方式对全世界的民事保护和减灾至关重要。了解喷发风格，特别是它们的过渡，最终使我们能够预测喷发行为，进行准确的危害评估，保护当地社区，并更好地了解可能具有经济价值的沉积。为了确定任何一座火山的喷发方式，我们需要知道岩浆是如何以及何时破裂的。对于理解厚岩浆（高黏度）的破裂，已有一套完善的理论，但这一知识不能应用于流岩浆（低黏度）。我们目前还不了解低粘度岩浆是如何破裂的，因此无法预测喷发方式，也无法准确地为民事保护和减灾提供信息。由于低粘度岩浆的喷发是地球和其他行星上最频繁和体积最丰富的火山活动形式，因此这种知识差距尤为重要。在这个未来领袖奖学金项目中，我将带领一个团队填补这一空白，并首次量化含气泡和/或晶体的流动（低粘度）岩浆是如何破裂的。这一目前缺失的关键信息最终将使我们能够预测一座火山是会爆发性喷发还是会喷涌而出。这一目标将通过多学科和多成分的方法来实现，结合我的实验室开发的世界独特的实验、数值模拟、实地研究和新颖的社区参与方法。大规模的新型实验室实验将在与自然火山爆发相关的条件下分离纯液体（类似的熔体）和液体、气泡和/或颗粒的混合物（类似的岩浆）。高速拍摄将记录拉伸过程，并确定液体是否破裂，以及如何破裂。这将使我能够“绘制出”导致岩浆流动（喷涌）或破碎（爆炸）的喷发条件。这种“行为图”将是第一个可以应用于世界范围内的含气泡和含晶体岩浆的地图。将这些新的实验结果与岩浆流动物理学相结合，将使我能够建立一个能够预测喷发方式（喷涌式还是爆发性）的数值模型。在整个研究过程中，这些产出将与火山观测站一起设计，以最好地支持其业务使用。为了加强我工作的影响和范围，我将在加拿大不列颠哥伦比亚省的Tseax火山部署实地技术。Tseax火山大约有320年的历史，是加拿大历史上最致命的火山喷发，造成多达2000人死亡，并摧毁了至少三个Nisga'a First Nation村庄。火山喷发出低黏度岩浆，并多次穿越爆发-喷涌过渡。现场研究与实验结果的结合将揭示导致致命爆炸-喷涌转变的原因。与Nisga'a First Nation的双边交流将把口头故事与科学研究结合起来，制作外联材料，在社区中激发热情、参与并发展复原力。我的目标是，我的新方法可以作为一种模式，用于支持世界各地受自然灾害影响的其他（土著）社区。

Ten percent of the world's population (i.e. 100s of millions) live within 100 km of an active volcano. Furthermore, this number is set to rise with the increasing global population and growing demand for natural resources. When volcanoes erupt, they can behave effusively, explosively, or in a combination of both. Effusive activity produces lava flows and toxic gases, whereas explosive activity involves the breakage (fragmentation) of magma, dispersing molten droplets and, when the fragmentation is efficient, lethal ash clouds/flows that can travel several kilometres. Thus, the eruption style (effusive vs. explosive) directly controls the type, spatial footprint and magnitude of the hazard and therefore risk to populations. Thus, establishing the style of activity is of utmost importance to civil protection and hazard mitigation worldwide. Understanding eruption styles, particularly their transitions, ultimately allows us to predict eruption behaviour, perform accurate hazard assessments, protect local communities and better understand resultant deposits that can be of econnomic value.To determine the eruptive style of any volcano, we need to know how and when the magma breaks. There is a well-established theory for understanding the breakage of thick (high viscosity) magma, but this knowledge cannot be applied to runny (low viscosity) magmas. We do not currently understand how low viscosity magmas break and therefore cannot predict eruption style and accurately inform civil protection and hazard mitigation. This knowledge gap is particularly significant because the eruption of low viscosity magmas is the most frequent and volumetrically abundant form of volcanism on Earth, and on other planets. In this Future Leaders Fellowship, I will lead a team to fill this gap and provide the first quantification of how runny (low viscosity) magmas containing bubbles and/or crystals break. This key information, currently missing, will ultimately enable us to predict whether a volcano will erupt explosively or effusively. This goal will be achieved through a multidisciplinary and multicomponent approach, combining world-unique experiments developed in my lab, numerical modelling, field studies and novel community engagement methods. Scaled novel laboratory experiments will pull apart pure liquids (analogue melts) and mixtures of liquid, bubbles and/or particles (analogue magmas) at conditions relevant to natural volcanic eruptions. High-speed filming will record the stretching process and identify if, and how the liquid breaks. This will enable me to 'map out' the eruption conditions that lead to magma flow (effusive) or fragmentation (explosive). This 'behaviour map' will be the first of its kind that can be applied to bubble- and crystal-bearing magmas worldwide. Synthesis of these new experimental results with magma flow physics will allow me to produce a numerical model that will be able to forecast eruption style (effusive vs. explosive). Throughout the research, these outputs will be designed with volcano observatories to best support their operational use.To enhance the impact and reach of my work, I will deploy field techniques at Tseax volcano, British Columbia, Canada. Tseax is ~320 years old and represents the deadliest eruption in Canadian history, having resulted in the deaths of up to 2000 people and destroyed at least three Nisga'a First Nation villages. The volcano erupted low viscosity magma and crossed the explosive-effusive transition multiple times. Integration of field studies with the experimental results will uncover what caused the fatal explosive-effusive transitions. Bilateral exchange with the Nisga'a First Nation will integrate oral stories with scientific research to produce outreach materials that enthuse, engage and develop resilience in the community. My aim is that my novel approach could be used as a model to support other (Indigenous) communities affected by natural hazards worldwide.