Collaborative Research: Linking pyroclastic surge dynamics and deposits through integration of field data, multiphase numerical modeling, and experiments

合作研究：通过现场数据、多相数值模拟和实验的整合，将火山碎屑涌动动力学与沉积物联系起来

• 批准号: 2034788
• 负责人: Amanda Clarke
• 金额: $ 27.4万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2034788&HistoricalAwards=false
• 关键词: Collaborative; Research; Linking; pyroclastic; surge

Explosive volcanic eruptions unleash flows of hot gases and particles called pyroclastic surges; these are deadly to humans and severely damage or destroy buildings and other infrastructure. Within the United States, pyroclastic surges are a potential hazard in many areas such as the Southwest and along the Cascade Range of the Pacific Northwest. Understanding parameters such as speed, pressure, temperature, and particle concentration is necessary to predict pyroclastic surge hazards and to take mitigative measures. Measurements of active pyroclastic surges are essentially impossible because of their unpredictability and the extreme conditions they create. As a result, we must use indirect methods: (1) detailed study of the deposits that were produced by pyroclastic surges, which can be studied after a volcano has gone quiet; (2) experiments aimed at replicating some aspects of the surges; and (3) computer modeling of the flows. This project uses these three methods iteratively. The work will provide new insights and tools to use in forecasting and mitigating volcanic hazards. In addition, the work will be done by a diverse, newly-formed multi-university team, will train two new Ph.D. students, and will strengthen partnership between academic researchers with the U.S. Geological Survey, which has primary responsibility for hazard assessment.Controls on the development of local facies in pyroclastic surge deposits as well as larger-scale parameters such as proximal-to-distal facies variations, runout, and damage potential are poorly understood. We will address the following research questions: (1) At the local scale (e.g., individual outcrop or group of outcrops), what are the relationships of bed forms and facies to sedimentation from suspended load, bed load flux, and local topography? (2) At the large scale (proximal to distal), what are the roles of sedimentation, topography, initial temperature, mass flux, and atmospheric entrainment on large-scale facies distribution, runout distance, and damage potential? The proposed work includes three components. (1) Detailed field studies will focus on two well-preserved, young deposits (Ubehebe volcano, California; Crater Elegante, Sonora), with documentation of facies, grainsize, and componentry as functions of distance from vent and local topographic setting. (2) Experiments will test and extend a simple relationship between dune-form parameters measurable in the field, bed load flux, and suspended load sedimentation flux. (3) Multiphase numerical modeling will use adaptive mesh refinement to resolve fluxes near the bed, will improve the numerical solution of coupling between gas and very fine ash (key for surge transport and deposition), and will use unstructured mesh technology to model surge transport over complex natural terrains. A new multiphase modeling tool that results from the project will be available for the research community at large.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.

火山喷发释放出炽热的气体和颗粒流，称为火山碎屑流；这些对人类来说是致命的，并严重损坏或摧毁建筑物和其他基础设施。 在美国境内，火山碎屑潮在许多地区（例如西南部和太平洋西北部的喀斯喀特山脉沿线）都是潜在的危险。了解速度、压力、温度和颗粒浓度等参数对于预测火山碎屑浪涌危害并采取缓解措施是必要的。由于火山碎屑流的不可预测性及其造成的极端条件，对活跃火山碎屑流的测量基本上是不可能的。 因此，我们必须采用间接的方法：（1）对火山碎屑流产生的沉积物进行详细研究，可以在火山平静后进行研究； (2) 旨在复制浪涌某些方面的实验； (3) 流动的计算机建模。 本项目迭代使用这三种方法。这项工作将为预测和减轻火山灾害提供新的见解和工具。 此外，这项工作将由一个多元化的、新组建的多大学团队来完成，该团队将培训两名新的博士生。学生，并将加强学术研究人员与美国地质调查局之间的合作关系，美国地质调查局主要负责灾害评估。控制火山碎屑潮沉积物中局部相的发育以及更大规模的参数，例如近端到远端相的变化、跳动和潜在损坏知之甚少。 我们将解决以下研究问题：（1）在局部尺度（例如，单个露头或露头群），床层形态和相与悬浮荷载、床荷通量和局部地形的沉积作用有何关系？ （2）在大尺度（近端到远端），沉积、地形、初始温度、质量通量和大气夹带对大尺度相分布、跳动距离和破坏潜力有何作用？拟议的工作包括三个组成部分。 (1) 详细的实地研究将集中于两个保存完好的年轻沉积物（加利福尼亚州乌贝黑比火山；索诺拉州埃莱甘特火山口），记录相、粒度和成分作为距喷口距离和当地地形环境的函数。 (2) 实验将测试和扩展现场可测量的沙丘形状参数、床荷通量和悬浮荷载沉降通量之间的简单关系。 (3) 多相数值模拟将使用自适应网格细化来解析床附近的通量，将改进气体和极细灰分之间耦合的数值解（浪涌输送和沉积的关键），并将使用非结构化网格技术来模拟浪涌输送复杂的自然地形。 该项目产生的新的多阶段建模工具将可供整个研究界使用。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。