Simulation of Rock Avalanches and Pyroclastic Flows

潜在的岩石雪崩和火山碎屑流的风险是全世界公共安全当局每年都要面对的几次问题（Tilling，1989 a）。我们建议开发一个3-D的计算机代码来模拟从危险的地质雪崩的质量和动量流，基于估计的原始体积的起始材料和它们的属性和准确的数字地形模型的表面。该模型将预测移动流和所产生的沉积物的横向和纵向厚度变化。这项工作将大大扩展谢里丹的Flow 3D程序（Kover，1994;谢里丹和Kover，1997）所提供的预报产品。该项目将包含几个要素：1。具有空气（雪崩）或热气体（火山碎屑流）基质的致密颗粒流的数学模型; 2.数据约束的基础上，最近在喀斯喀特山脉和火山碎屑流在圣海伦斯山和科利马，墨西哥雪崩的实地研究; 3。水槽和斜坡实验室试验，以测试模型在小比例尺;和4。模拟研究地点未来潜在事件的情景。模拟代码将与实验室和现场研究密切合作，提供计算机建模与实验结果的保真度。我们模拟的基础将是源体积和流出数据（存款剖面、厚度等）的估计。真实的雪崩和水流以及当前地形的精确DEM。这些模型将提供速度历史、流动路径、流动厚度和模拟的平面面积，所有这些都是三维的。输出的显示格式将适合公共安全官员和科学家的解释。结果将被反拟合到火山碎屑流数据从Unzen，苏弗里埃山，山。圣海伦斯，和火山科利马和雪崩数据从喀斯喀特火山。根据我们的基准，该代码将使我们能够预测未来的本地危险在这些和其他网站，包括皮科德奥里扎巴，雷尼尔山，和亚当斯山。由此产生的模型应该有助于当局为特定的危险地区设计缓解计划。

SheridanEAR-0087665The risk of potential rock avalanches and pyroclastic flows is a problem that public safetyauthorities around the world face several times a year (Tilling, 1989a). We propose to develop a 3-D computer code to simulate the mass and momentum flow from dangerous geologic avalanches, based on estimates of original volume of the starting materials and their properties and an accurate digital terrain model of the surface. The model will forecast lateral and longitudinal thickness variations in both the moving flow and the resulting deposits. This effort will greatly extend the forecasting products now provided by the successful Flow3D code of Sheridan (Kover, 1994; Sheridan and Kover, 1997). This project will contain several elements: 1. a mathematical model for dense grain flows with an air (avalanche) or hot gas (pyroclastic flow) matrix; 2. data constraint based on field studies of several recent avalanches in the Cascade Range and pyroclastic flows at Mount St. Helens and Colima, Mexico; 3. flume and inclined slope laboratory experiments to test the model at a small scales; and 4. simulation of scenarios of potential future events at the study sites. The simulation code will be developed in close concert with laboratory and field studies, providing fidelity of the computer modeling with experimental results. The basis of our simulations will be estimation of source volumes and runout data (deposit profile, thickness, etc.) of actual avalanches and flows and accurate DEMs of current topography. The models will provide velocity histories, flow paths, flow thickness, and planimetric areas of the simulations, all in three dimensions. The output display format will be suitable for interpretation by public safety officials as well as scientists. The results will be back-fitted to pyroclastic flow data from Unzen,Soufriere Hills, Mt. St. Helens, and Volcano Colima and avalanche data from Cascade volcanoes. Based on our benchmarking, the code will allow us to forecast future local hazards at these and other sites including Pico de Orizaba, Mount Rainier, and Mount Adams. The resulting model should help authorities design mitigation plans for specific dangerous areas.