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

世界上10%的人口(即数以亿计的人)生活在活火山周围100公里以内。此外，随着全球人口的增加和对自然资源需求的增加，这一数字将会上升。当火山喷发时，它们的行为可能是热情洋溢的，也可能是爆炸性的，或者两者兼而有之。喷流活动产生熔岩流和有毒气体，而爆炸活动涉及岩浆的破碎(碎裂)，分散熔滴，如果碎裂有效，则会产生致命的火山灰云/流，可传播数公里。因此，喷发类型(喷发与喷发)直接控制危险的类型、空间足迹和大小，因此对人口的风险。因此，确立活动方式对全世界的民事保护和减灾至关重要。了解喷发方式，特别是它们的转变，最终使我们能够预测喷发行为，进行准确的危险评估，保护当地社区，并更好地了解所产生的具有经济价值的矿床。要确定任何火山的喷发方式，我们需要知道岩浆如何以及何时破裂。对于理解厚(高粘度)岩浆的破裂，有一个成熟的理论，但这一知识不能应用于流动(低粘度)岩浆。我们目前不了解低粘度岩浆是如何破裂的，因此无法预测喷发方式，并准确地为民用保护和减灾提供信息。这一认识差距尤其显著，因为低粘度岩浆的喷发是地球和其他星球上最频繁、体积最丰富的火山活动形式。在这个未来领导者联谊会中，我将带领一个团队填补这一空白，并首次量化含有气泡和/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喷发还是会喷发。这一目标将通过多学科和多组成部分的方法来实现，将我的实验室开发的世界独一无二的实验、数值模拟、实地研究和新颖的社区参与方法结合起来。规模化的新实验室实验将在与自然火山喷发相关的条件下分离纯液体(模拟熔体)和液体、气泡和/或颗粒的混合物(模拟岩浆)。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(热流)或碎裂(爆炸性)的喷发条件。这一“行为图”将是第一个可以应用于全球含气泡和含晶体岩浆的此类地图。将这些新的实验结果与岩浆流动物理学相结合，将使我能够产生一个能够预测喷发方式(喷发与爆炸)的数值模型。在整个研究过程中，这些输出将与火山观测站一起设计，以最好地支持它们的业务使用。为了增强我的工作的影响和覆盖范围，我将在加拿大不列颠哥伦比亚省的Tseax火山部署野外技术。Tseax有320年的历史，是加拿大历史上死亡人数最多的火山喷发，造成多达2000人死亡，至少摧毁了三个尼斯加第一民族村庄。火山喷发出低粘度岩浆，多次跨越爆炸-喷涌过渡。将实地研究与实验结果结合起来，将揭示是什么导致了致命的爆炸-喷发转变。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，以制作宣传材料，激发社区的热情，使其参与并发展社区的复原力。我的目标是，我的新方法可以被用作支持世界各地受自然灾害影响的其他(土著)社区的典范。

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.