Simulation of Rock Avalanches and Pyroclastic Flows

潜在的岩石雪崩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几次的问题（Tilling, 1989a）。我们建议开发一个三维计算机代码来模拟危险地质雪崩的质量和动量流动，基于对原始材料的体积及其性质的估计和精确的地表数字地形模型。该模型将预测移动流和沉积的横向和纵向厚度变化。这一努力将极大地扩展Sheridan成功的Flow3D代码（Kover, 1994; Sheridan and Kover, 1997）所提供的预测产品。该项目将包含几个要素：1。以空气（雪崩）或热气体（火山碎屑流）为基质的致密颗粒流的数学模型；2. 基于喀斯喀特山脉最近几次雪崩和墨西哥圣海伦斯山和科利马火山碎屑流实地研究的数据约束；3. 水槽和斜面室内小尺度试验对模型进行检验；和4。在研究地点模拟未来可能发生的事件。模拟代码将与实验室和实地研究密切配合开发，提供计算机模拟与实验结果的保真度。我们模拟的基础将是估计实际雪崩和流动的源体积和跳动数据（沉积物剖面，厚度等）以及当前地形的准确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Unzen，Soufriere Hills, Mt. Helens和Volcano Colima的火山碎屑流数据以及来自Cascade火山的雪崩数据进行反向拟合。基于我们的基准测试，该规范将使我们能够预测这些地点以及其他地点（包括Pico de Orizaba、雷尼尔山和亚当斯山）未来的当地灾害。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.