Collaborative Research: Investigating the role of topography and magma properties on dike pathways beneath stratovolcanoes using field data, analogue experiments, and modeling

火山爆发是美国主要的自然灾害，美国大约有169座潜在的活火山，其中许多火山位于人口迅速增长的地区。虽然监测火山动荡无疑对喷发预测很重要，但准确解释监测数据和预测未来火山活动需要对岩浆从地壳储存区向地表输送的过程有科学的了解。这个项目将提高人们对是什么原因导致岩浆在雷尼尔山和胡德山等大型层状火山的地下向不同方向移动的认识。这项工作将测试岩浆的物理性质和火山大厦的大小如何影响喷发位置，这一点目前知之甚少。该项目支持研究生和本科生的跨学科培训，以及编写将在大学课堂上实施的教育材料，并向公众提供，供广泛的课堂和在线教育使用。该项目的主要目标是确定是什么控制了层状火山下岩浆岩脉的路径。层状火山下地壳的应力扰动被认为会影响上升的岩脉的传播方向，可能会阻止岩脉的传播或使岩脉向侧翼偏转，并导致低海拔地区的火山爆发，这可能对当地社区造成危险。这个为期三年的项目将采用一种协同的方法，将地质现场数据、模拟明胶实验和数值模型结合起来，研究由层状火山负荷和岩浆性质变化产生的应力场如何影响从地壳源上升的岩脉的几何形状和传播。拟议的工作包括地质测绘和从科罗拉多州夏季库恩（Summer Coon）被侵蚀的层状火山暴露的径向岩脉序列中收集样本，以测量岩脉露头的几何形状、流动结构和岩浆的物理性质，如密度和泡状。使用一种新的实验装置和受现场数据约束的输入参数，明胶实验将包括在模拟建筑物下注入岩浆类似物，以研究不同建筑物高度/坡度、岩浆密度和岩脉注入深度对岩脉扩展的影响。最后，现场和实验结果将为新的数值模型提供信息，这些模型旨在评估火山大厦下的地壳应力，并研究平面内岩脉传播方向如何随着大厦几何形状、岩浆浮力、初始岩浆压力和岩脉注入深度的变化而变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Volcanic eruptions are a major natural hazard in the United States, where there are about 169 potentially active volcanoes, many of which are located in areas with rapidly expanding populations. Although monitoring volcanic unrest is undoubtedly important to eruption forecasting, accurate interpretation of monitoring data and prediction of future volcano behavior require a scientific understanding of the processes that transport magma out of storage regions in the Earth’s crust and towards the surface. This project will enhance knowledge about what causes magma to move in different directions through the subsurface under large stratovolcanoes such as Mount Rainier and Mount Hood. The work will test how the physical properties of magma and the size of the volcanic edifice influence eruption location, which is currently poorly understood. The project supports interdisciplinary training of graduate and undergraduate students, as well as the development of educational materials that will be implemented in university classrooms and made available to the public for broad classroom and online educational use.The primary objective of this project is to determine what controls the pathways of magmatic dikes under stratovolcanoes. Stress perturbations in the crust beneath a stratovolcano are thought to impact the propagation direction of ascending dikes, potentially arresting propagation or deflecting dikes toward the flanks and causing eruptions at lower elevations that can be hazardous to local communities. The proposed three-year project will employ a synergistic approach that integrates geologic field data, analogue gelatin experiments, and numerical models to investigate how the stress field generated by the load of stratovolcanoes and variations in magma properties impact the geometry and propagation of dikes ascending from crustal sources. The proposed work includes geologic mapping and sample collection from the radial dike sequence exposed at Summer Coon, an eroded stratovolcano in Colorado, to measure dike outcrop geometries, flow fabrics, and physical magma properties like density and vesicularity. Using a novel experimental setup and input parameters constrained by field data, gelatin experiments will include injecting magma analogues beneath a simulated edifice to investigate the impacts of variable edifice height/slopes, magma densities, and dike injection depths on dike propagation. Finally, field and experimental results will inform new numerical models designed to evaluate crustal stresses beneath a volcanic edifice and investigate how in-plane dike propagation directions vary as a function of edifice geometry, magma buoyancy, initial magma pressures, and dike injection depths.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.