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

火山喷发是美国的一大自然灾害，美国大约有169座潜在活火山，其中许多位于人口迅速膨胀的地区。尽管监测火山动乱无疑对喷发预测很重要，但准确解释监测数据和预测未来的火山行为需要对将岩浆从地壳储存区输送到地表的过程有科学的了解。该项目将加强对是什么导致岩浆在雷尼尔山和胡德山等大型层状火山下的地下以不同方向流动的知识。这项工作将测试岩浆的物理性质和火山建筑物的大小如何影响喷发地点，目前人们对此知之甚少。该项目支持研究生和本科生的跨学科培训，以及开发教材，这些教材将在大学课堂上实施，并向公众提供广泛的课堂和在线教育用途。该项目的主要目标是确定是什么控制了层状火山下面的岩浆岩墙的路径。层状火山下方地壳中的应力扰动被认为会影响上升岩墙的传播方向，可能会阻止岩墙的传播或使岩墙向两侧偏转，并在较低海拔引起喷发，这可能会对当地社区造成危险。拟议的为期三年的项目将采用一种协同方法，将地质场数据、模拟凝胶实验和数值模型结合起来，以调查层状火山负载产生的应力场和岩浆性质的变化如何影响从地壳来源上升的岩墙的几何形状和传播。拟议的工作包括地质测绘和从科罗拉多州被侵蚀的层状火山Summer Coon暴露的放射状岩脉序列中采集样本，以测量岩脉露头几何形状、流动组构以及密度和孔洞等物理岩浆属性。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，以研究不同的建筑物高度/坡度、岩浆密度和堤坝注入深度对堤坝传播的影响。最后，现场和实验结果将提供新的数值模型，用于评估火山建筑物下的地壳应力，并研究平面内堤坝传播方向如何随建筑物几何形状、岩浆浮力、初始岩浆压力和堤坝注入深度的变化而变化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.