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.

河流的砾石和卵石输送控制着河道的变化，因此对于地貌学家和河流工程师来说非常重要。估计底泥输送率的最常用方法是基于水槽实验的经验校准关系。 然而，很难评估这种关系如何有效地预测大河流极端事件期间的输运率，因为底质输运的定量测量是劳动密集型的，并且在高流量时通常很难获得。出于后勤原因，大多数床载研究都是在小山涧中进行的。颗粒对河床的撞击会传递动量，进而产生弹性（地震）波。因此，地震学（地球弹性波的研究）可能会限制河流的底质输送率。 利用仪器齐全的集水区，对沉积物在河道中移动的时间和速度进行独立限制，我们将部署一系列地震仪来测试运输过程中沉积物与河床碰撞产生地震波的理论预测。 更清楚地了解粗沉积物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（例如桥梁、水坝、道路）至关重要。 预测粗沉积物输送的方法通常是在受控环境下开发的，在大洪水中可能不准确，而此时预测沉积物运动至关重要。 利用现有科学（地震学）的新颖应用，我们正在开发一种无需在河流中部署任何仪器即可测量大河流中床质输送的方法。 这项工作有可能大大提高我们廉价、安全、高效地监测河流沉积物运动的能力，同时增进对影响河流底泥输送速率的过程的了解。 此外，该项目还将有一个外展部分，其中本科生地质学班将使用此处开发的方法进行沉积物运输监测练习。