Experiments on debris-flow initiation from runoff

在陡峭的山区地形，泥石流可以控制泥沙运移和基岩河道切割，并驱动景观变化。 虽然泥石流通常是由滑坡产生的，但越来越多的证据表明，泥石流是由径流和地表径流产生的，特别是在陡峭的高山景观和野火之后，干燥、松散的沉积物在失败之前聚集在通道和斜槽中。 泥石流产生的径流的启动机制还没有很好的理解。 为了解决这一问题，将进行一系列实验，这些实验将构成测试和发展山区渠道泥石流起动理论的基线。 实验将在加州理工学院一个新的最先进的设施中进行，该设施专门用于研究非常陡峭的斜坡上的沉积物输运过程。 拟议的工作将测试四个假设的泥石流的发病范围广泛的渠道坡度和沉积物的大小。 这项工作的预期成果是对控制泥石流从通道内开始的基本机制的新认识，以及将泥石流开始与地形（如通道坡度）和环境扰动（如洪水和野火）联系起来的预测模型的开发。 泥石流是全世界山区最危险和代价最高的灾害之一。 这项工作将提高我们对泥石流发生的理解，并有助于我们预测灾害和制定更好的土地利用战略。 研究结果将应用于洛杉矶地区，在那里，野火后径流产生的泥石流很常见，在导致生命损失和财产损失的情况下。这些结果将通过期刊出版物向公众提供，并通过GeomorphLectures Wiki向科学教学界提供，该Wiki旨在成为年轻教育工作者的资源。 教育和推广活动包括培训本科生、博士和博士后水平的科学家，以及通过与加利福尼亚州帕萨迪纳联合学区合作，志愿者进行课堂演示和实验室图尔斯参观。

In steep mountain terrain, debris flows can dominate sediment transport and bedrock channel incision, and drive landscape change. Although debris flows are often generated from landslides that fluidize upon failure, there is increasing evidence for the importance of debris flows generated from runoff and overland flow, especially in steep alpine landscapes and following wildfire where dry, loose sediment collects in channels and chutes prior to failure. The initiation mechanisms for debris-flow generation from runoff are not well understood. To address this, a series of experiments that will form the baseline to test and develop theory for debris-flow initiation in mountain channels will be conducted. The experiments will take place in a new state-of-the-art facility at the California Institute of Technology designed specifically to investigate sediment transport processes on very steep slopes. The proposed work will test four hypotheses concerning the onset of debris flows over a wide range of channel slopes and sediment sizes. The expected outcome from this work is new insight into the underlying mechanics that control debris-flow initiation from within channels, and the development of predictive models that link debris flow initiation to topography, such as channel slope, and environmental perturbations, such as floods and wildfires. Debris flows are one of the most dangerous and costly hazards of mountainous terrain worldwide. This work will improve our understanding of debris flow initiation and aid in our ability to forecast hazards and develop better land-use strategies. The results will have applications for the Los Angeles area where runoff-generated debris flows are common following wildfire, in cases resulting in loss of life and property damage. These results will be made available to the public through journal publications and to the scientific teaching community through the GeomorphLectures Wiki, designed to be a resource for young educators. Educational and outreach activities include training scientists at the undergraduate, PhD and postdoctoral levels, and volunteer classroom presentations and laboratory tours through collaborations with the Pasadena Unified School District, CA.