Collaborative Research: The Role of Debris Flows in Shaping Mountainous Terrain

该项目将调查泥石流在形成山脉方面的作用。这是地貌学中的一个基本问题，因为泥石流显然是陡峭地形中非常重要的运输过程，每年都会携带大量泥沙。然而，人们对它们在塑造地形中的作用知之甚少，以至于它们在景观演变模型中基本上被忽视了。该项目将通过数据收集、地形分析、过程监控以及模型开发和测试的综合计划，帮助填补这一关键的知识缺口。数据将来自两个相辅相成的研究地区，这两个地区是世界上研究泥石流动力学最好的地区之一。第一个是意大利的亚平宁中部，那里关于第四纪断块运动速率的非常详细的数据为研究地形对构造强迫的响应提供了一个无与伦比的天然实验室。第二个是俄勒冈海岸山脉，在那里，强大的过程研究历史为测试和完善泥石流冲刷形成山谷的模型提供了丰富的数据库。在亚平宁山脉，地貌测绘和自动化过程监测将描绘出水流动力学的本质，包括频率-幅度特征和河床磨损过程。对经历不同已知相对抬升速率的约200条陡峭的山区河道进行数字地形分析，将产生一个关于泥石流为主的河道对构造强迫的响应的大型数据库。这些数据将被用来开发、测试和改进一个基于物理的一维模型，该模型是在不同的构造抬升速率下，由泥石流侵蚀驱动的山谷长剖面演化。在俄勒冈海岸山脉，人们对泥石流的性质和范围已经有了很多了解，研究将集中在现有的景观演变模型中开发泥石流模块，并测试该模型解释观测到的地形、土壤厚度和过程动力学分布的能力。更广泛的影响：关于陡峭山区源头及其对构造强迫的反应的成功理论在土地利用影响分析和地震危险评估中得到了应用。该项目将培养两名研究生，并让他们在国内和国际上建立联系。通过开发开放源码的图形界面和可视化工具，将使前沿景观演变模型更容易获得。该项目的外展部分将扩大研究的影响，将项目材料，包括最先进的景观演变可视化，带入本科生课堂，作为一套指导性探究练习。将通过在经济和种族多元化的城市学区与高中科学教师一起举办讲习班，为中学一级开发和应用符合标准的版本。

This project will investigate the role of debris flows in shaping mountain ranges. This is a fundamental problem in geomorphology because debris flows are clearly very important transport processes in steep terrain, carrying vast quantities of sediment every year. Yet so little is known about their role in shaping terrain that they have been essentially ignored in landscape evolution models. This project will help fill this critical knowledge gap with a comprehensive program of data collection, topographic analysis, process monitoring, and model development and testing. Data will come from two complementary study areas that are among the best in the world for studying debris-flow dynamics. The first is the central Apennines of Italy, where remarkably detailed data on rates of Quaternary fault-block motion offer an unparalleled natural laboratory for studying landscape response to tectonic forcing. The second is the Oregon Coast Range, where a strong history of process research provides a rich database for testing and refining models of valley formation by debris-flow scour. In the Apennines, geomorphic mapping and automated process monitoring will paint a picture of the nature of flow dynamics, including frequency-magnitude characteristics and processes of bed wear. Digital topographic analysis of ~200 steep mountain channels undergoing different known rates of relative uplift will yield a large database on the response of debris-flow-dominated channels to tectonic forcing. These data will be used to develop, test, and refine a 1D physically based model of valley long-profile evolution driven by debris-flow erosion under varying rates of tectonic uplift. In the Oregon Coast Range, where much is already known about the nature and extent of debris flows, research will concentrate on developing a debris-flow module in an existing landscape evolution model, and testing the ability of this model to account for observed distributions of topography, soil thickness, and process dynamics. Broader impacts: A successful theory for steep mountain headwaters and their response to tectonic forcing has applications in land-use impact analysis and seismic-hazard assessment. This project will train two graduate students and give them national and international contacts. A cutting-edge landscape evolution model will be made more accessible by the development of open-source graphical interface and visualization tools. The project's outreach component will broaden the impact of the research by bringing project materials, including state-of-the-art visualizations of landscape evolution, into the undergraduate classroom as a set of guided-inquiry exercises. Development and application of a standards-aligned version for the secondary- school level will be piloted through workshops with high school science teachers in an economically and racially diverse urban school district.