Collaborative Research: Unlocking The Seismic Signature Of Rivers

合作研究：解锁河流的地震特征

• 批准号: 1148176
• 负责人: Colin Stark
• 金额: $ 6.39万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1148176&HistoricalAwards=false
• 关键词: Collaborative; Research; Unlocking; Seismic; Signature

Gravel and cobble transport by rivers governs channel change, and is therefore of great importance to geomorphologists and river engineers. The most commonly used approaches to estimating bedload transport rates are empirically calibrated relationships based on flume experiments. However, it is difficult to assess how effectively such relationships predict transport rates during extreme events in large rivers because quantitative measures of bedload transport are labor intensive and, at high flows, often dangerous to obtain. For logistical reasons, most bedload studies have been carried out in small mountain streams. Particle impacts on the river bed transfer momentum, which in turn generates elastic (seismic) waves. Therefore, seismology (the study of elastic waves in the Earth) can potentially constrain bedload transport rates in rivers. Taking advantage of a well-instrumented catchment with independent constraints on when and at what rate sediment moves in the channel, we will deploy an array of seismometers to test theoretical predictions for the generation of seismic waves from bedload sediment impacts with the bed during transport. Understanding more clearly when and at what rate coarse sediment moves in river channels is essential for planning infrastructure in and adjacent to rivers (e.g., bridges, dams, roads). Approaches to predicting coarse sediment transport are typically developed in controlled settings and can be inaccurate in large floods, when it is most critical to be able to predict sediment movement. Using a novel application of an existing science (seismology), we are developing an approach to measuring bedload transport in large rivers without requiring the deployment of any instrumentation in the river. This work has the potential to greatly improve our capacity to cheaply, safely, and efficiently monitor sediment movement in rivers while simultaneously advancing understanding of the processes influencing bedload transport rates in rivers. Additionally, this project will have an outreach component in which an undergraduate geology class will conduct a sediment transport monitoring exercise using the approach developed here.

河流中的砾石和卵石输运控制着河道的变化，因此对地貌学家和河流工程师来说非常重要。最常用的方法来估计推移质输沙率经验校准关系的水槽实验的基础上。 然而，这是很难评估如何有效地预测运输率在大型河流的极端事件，因为推移质运输的定量措施是劳动密集型的，在高流量，往往是危险的。由于后勤方面的原因，大多数推移质研究都是在小型山溪中进行的。颗粒撞击河床传递动量，进而产生弹性（地震）波。因此，地震学（研究地球中的弹性波）可以潜在地限制河流中的推移质输运率。 利用一个仪器齐全的集水区，独立的限制，沉积物在通道中移动的时间和速度，我们将部署一个地震仪阵列，以测试理论预测的推移质沉积物的影响，在运输过程中产生的地震波。 更清楚地了解粗泥沙在河道中移动的时间和速度对于规划河流及其附近的基础设施至关重要（例如，桥梁、水坝、道路）。 预测粗泥沙输运的方法通常是在受控环境中制定的，在大洪水中可能不准确，而此时能够预测泥沙运动是最关键的。 使用现有的科学（地震学）的新应用，我们正在开发一种方法来测量在大河推移质运输，而不需要在河流中部署任何仪器。 这项工作有可能大大提高我们廉价、安全、有效地监测河流泥沙运动的能力，同时促进对影响河流推移质输沙率的过程的了解。 此外，该项目将有一个推广部分，其中一个本科地质学班将使用这里开发的方法进行沉积物运输监测。