Simulation of Rock Avalanches and Pyroclastic Flows

SHERIDAN EAR-0087665潜在的岩石崩塌和火山碎屑流的风险是世界各地的公共安全当局每年面临的一个问题(Tling，1989a)。我们建议开发一个三维计算机程序来模拟危险地质雪崩的质量和动量流，其基础是对起始物质及其性质的估计和地表精确的数字地形模型。该模型将预测移动的水流和由此产生的沉积物的横向和纵向厚度变化。这一努力将极大地扩展Sheridan(Kover，1994；Sheridan and Kover，1997)成功的Flow3D代码所提供的预报产品。该项目将包含几个要素：1.具有空气(雪崩)或热气(火山碎屑流)矩阵的致密颗粒流动的数学模型；2.基于对最近级联山脉的几次雪崩和墨西哥圣海伦斯山和科利马的火山碎屑流的实地研究的数据约束；3.在小尺度上测试模型的水槽和倾斜坡度实验室实验；以及4.模拟研究地点未来可能发生的事件的情景。模拟代码将与实验室和现场研究密切合作开发，以确保计算机模拟与实验结果的保真度。我们模拟的基础将是对源体积和跳动数据(沉积剖面、厚度等)的估计。真实的雪崩和水流以及当前地形的准确数字高程模型。这些模型将提供模拟的速度历史、流动路径、流动厚度和平面面积，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。结果将与来自蒙大拿州苏弗里尔山温岑的火山碎屑流数据进行反向拟合。圣海伦斯、科利马火山和喀斯喀特火山的雪崩数据。根据我们的基准，该代码将使我们能够预测这些地点和其他地点未来的局部危险，包括Pico de Orizaba、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.