Controls on ridgeline profile morphology

山体滑坡、泥石流和河流洪水等自然灾害威胁着生命和基础设施。地质学家和地质工程师致力于识别易发生自然灾害的地区，并预测何时会发生灾害，从而提高公共安全。然而，这项工作需要对地貌如何侵蚀和演变的物理理解。地质学家花了一个多世纪研究河流和山坡侵蚀，但令人惊讶的是，在所有景观中都存在着一种地形特征，到目前为止几乎没有人进行过研究。这些目前未描述的地形特征是山脊线，即沿分隔两个相邻流域的地形分水岭的高程剖面。目前对山脊线如何形成和侵蚀缺乏了解，限制了对地貌起伏分布的预测(即地貌的陡度如何变化)，这是预测滑坡、泥石流发生、河流沉积物流量等的关键。这项建议旨在了解形成脊线形状的过程。实现这一点将通过提高我们对景观如何形成的理解来促进基础科学的发展，并可能导致在预测自然灾害方面的改进。除了这些好处，该项目还包括对未来的中学教师进行基础地球科学方面的培训。了解地球科学可以帮助学生了解和理解气候变化等社会威胁。许多中学教师缺乏地球科学培训，为未来的教师提供这种培训可以提高未来学生的地球科学教育质量。具体地说，本项目将对现有的描述山脊线形状的理论进行修改和补充。这项工作将测试关于山脊线坡度的控制、沿山脊线局部山峰和鞍座的存在以及山脊线“鼻子”(山脊向下俯冲与河口相接的部分)的三个假说。每个假说都将根据自然景观的现场数据和先前存在的实验室实验进行验证，这些实验中的景观是在受控条件下进化的。该项目未来的教师培训部分包括为期12周的专业发展课程。未来的教师(从内华达·里诺大学的一个培训项目招募)将获得900美元的津贴，将被教授适合中学教学的基本地球科学概念，并有机会制定地球科学课程计划并在当地中学讲授这些课程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Natural hazards such as landslides, debris flows, and river flooding threaten lives and infrastructure. Geologists and geological engineers work to identify areas prone to natural hazards and predict when hazards will occur, thereby improving public safety. However, this work requires a physics-based understanding of how landscapes erode and evolve. Geologists have spent over a century studying river and hillslope erosion, but, surprisingly, there is a topographic feature present in all landscapes that has seen almost no study to date. These currently undescribed topographic features are ridgelines – the elevation profile along a topographic divide separating two adjacent watersheds. The current lack of understanding of how ridgelines are shaped and eroded limits predictions of the distribution of landscape relief (i.e., how the steepness of landscapes varies), which is key to predict landsliding, debris flow occurrence, river sediment flux and more. This proposal seeks to understand the processes that set ridgeline shape. Accomplishing this will advance basic science by improving our understanding of how landscapes are formed, and can also lead to improvements in predicting natural hazards. Beyond these benefits, the project includes training for future middle school teachers in basic earth science. Understanding earth science can help students contextualize and understand societal threats such as climate change. Many middle school teachers lack earth science training; providing this training to future teachers can improve the quality of geoscience education for future students. Specifically, this project will modify and add to existing theory to describe the shape of ridgelines. The work will test three hypotheses about the controls on ridgeline slope, the presence of local peaks and saddles along ridgelines, and the form of ridgeline ‘snouts’ (the portion where the ridge dives down to meet the river outlet). Each hypothesis will be tested against a combination of field data from natural landscapes and pre-existing laboratory experiments where landscapes are evolved under controlled conditions. The future teacher training portion of the project consists of a 12-week long professional development course. Future teachers (recruited from a training program at the University of Nevada Reno) will earn $900 stipends and will be taught basic geoscience concepts appropriate for middle school teaching and have the opportunity to develop geoscience lesson plans and present these lessons in local middle schools.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.