CMG: Studies of Sediment Gravity Flows

CMG：沉积物重力流研究

• 批准号: 0620991
• 负责人: E Bruce Pitman
• 金额: --
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0620991&HistoricalAwards=false
• 关键词: CMG; Studies; Sediment; Gravity; Flows

This project combines simulations of pyroclastic flows and surges and related gravity currents based on meshfree methods, together with modeling and analysis, all tested against lab and field data. The Least Squares Meshfree Method forms the core of a proposed particle-based computational method for simulations. Adaptivity - injecting new particle basis functions, increasing basis function order of approximation - will be introduced, allowing accurate resolution of free surfaces and other fundamental structures within the flows. Mathematical and computational modeling will extend the current Least Squares methodology to flows which are composed of a mixture of gas and grains, and to flows with significant thermal content. Mathematical analysis will elucidate the smoothing properties of the method, to ensure a robust and accurate simulation technology, and to enable translation of the method to other geophysical mass flow systems. Simulations will be validated against laboratory experiments, and its predictive efficacy tested against field results. In this way, mathematical theory and geological experiment together can develop a new approach to the mathematical modeling of geophysical flow systems.Pyroclastic flows are heavier-than-air gas-particle mixtures resulting from volcanic activity. Pyroclastic flows can travel at velocities from 10-100 m/sec, and can attain temperatures upwards of 1000 degrees C. Pyroclastic flows can have high density, and move down mountainsides and under water, or they can be of low density, and lift over mountains and across water. Because of their speed, temperature and volume, pyroclastic flows pose an enormous risk to populations within miles of the volcanic source. Evidence of their destructive power can be seen Mount St. Helens, WA, USA, Soufriere Hills Volcano, Montserrat, Mount Pinatubo, Phillipines, and Colima Volcano, Mexico, among other sites. Although pyroclastic flows and surges (basically a dilute pyroclastic flow) are carefully studied, a detailed understanding of the dynamics of the stratified, flowing material over natural topography is not in hand; predictive capability a scientifically-based assessment of what regions are at high risk is lacking. As scientists, it is important to be able to rationally assess risk and communicate the nature of that risk to local public safety officials. An interaction between science and society based on a clear understanding of the phenomenology leading to the construction of reasonable hazard risk maps will, hopefully, save lives. This program of mathematical and computational research, coupled with laboratory and field study, will better predict the speed and extent of pyroclastic flows and surges. These results will serve the public interest by aiding the production of trustworthy hazard risk maps.

该项目结合了基于无网格方法的火山碎屑流和浪涌以及相关重力流的模拟，以及建模和分析，所有这些都针对实验室和现场数据进行了测试。最小二乘无网格法是一种基于粒子的模拟计算方法的核心。自适应性-注入新的粒子基函数，增加基函数的近似阶-将被引入，允许准确的自由表面和流动内的其他基本结构的分辨率。数学和计算建模将扩展目前的最小二乘法的流量是由气体和谷物的混合物，并与显着的热含量的流量。数学分析将阐明该方法的平滑特性，以确保稳健和准确的模拟技术，并使该方法能够转化为其他地球物理质量流系统。模拟将根据实验室实验进行验证，并根据现场结果测试其预测效力。火山碎屑流是火山活动产生的比空气更稀薄的气-粒混合物。火山碎屑流可以以10-100米/秒的速度移动，温度可以达到1000摄氏度以上。火山碎屑流可以具有高密度，并沿着山坡和水下移动，或者它们可以具有低密度，并越过山脉和水面。由于其速度、温度和体积，火山碎屑流对火山源数英里内的人口构成巨大风险。其破坏力的证据可以看到圣海伦斯山，华盛顿州，美国，苏弗里埃山火山，蒙特塞拉特，皮纳图博山，菲律宾和科利马火山，墨西哥，以及其他网站。虽然火山碎屑流和浪涌（基本上是一个稀释的火山碎屑流）进行了仔细的研究，分层的动态，流动的物质在自然地形的详细了解是不是在手;预测能力，哪些地区是在高风险的科学为基础的评估是缺乏的。作为科学家，重要的是要能够合理地评估风险，并将风险的性质传达给当地的公共安全官员。科学与社会之间的互动建立在对现象学的清晰理解的基础上，从而导致构建合理的灾害风险地图，这将有望拯救生命。这一数学和计算研究方案，加上实验室和实地研究，将更好地预测火山碎屑流和浪涌的速度和范围。这些结果将有助于制作值得信赖的灾害风险地图，从而为公众利益服务。