Collaborative Research: RAPID: The fate of landslide-derived sediment following tropical cyclones: a case study of Hurricane Fiona in Puerto Rico

合作研究：RAPID：热带气旋后滑坡沉积物的命运：波多黎各飓风菲奥娜的案例研究

• 批准号: 2301379
• 负责人: Kenneth Hughes
• 金额: $ 2.18万
• 依托单位: University of Puerto Rico Mayaguez
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-01 至 2023-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301379&HistoricalAwards=false
• 关键词: Collaborative; Research; RAPID; fate; landslide

From September 18-20, 2022 Hurricane Fiona delivered more than 64 cm of rainfall to the island of Puerto Rico. This excessive precipitation caused mass wasting and flooding across the island, similar to the effects of Hurricane María in 2017. Both events represent extraordinary opportunities to study the impact of tropical cyclones on the evolution of a high relief, tropical landscape. This project will support two deployments of scientists and equipment to collect time-sensitive and perishable data from two catchments in southern Puerto Rico strongly impacted by mass wasting after the hurricane. Using these catchments as a model study area the investigators will: 1. survey the topography of landslide deposits, scars, and post-landslide river aggradation using drone-based structure-from-motion photogrammetry; 2. collect samples of river sediment downstream of landslide areas for grain size analysis and cosmogenic nuclide tracing of landslide-derived sediment, 3. monitor and record the movement of still-unstable landslides and actively aggrading river channels with time-lapse cameras. The project will be collaborative with co-investigators based in Puerto Rico and coordinated in concert with federal and local scientists working in hazards assessment and prevention. Field work deployments will engage at least 3 graduate and 3 undergraduate students.For more than sixty years, geologists have debated the contribution of large, yet infrequent storm events to the long-term evolution of eroding landscapes. For large storms like tropical cycles, the immediate geomorphic impact to tropical landscapes may be obvious: mass wasting and flooding. However, the extended response of tropical landscapes to the storm event is often more complex, and measurement of landscape response requires repeated observations across a catchment area, beginning immediately after the storm event. This project supports collection of time-sensitive and perishable data to explore three hypotheses concerning the response of a tropical landscape to landslides and flooding caused by a tropical cyclone. Specifically, the investigators will address the questions: 1. Where (and why) do storm events destabilize hillslopes? by surveying landslide scars and deposits in-person, monitoring still-unstable hillslopes with time-lapse cameras, and mapping landslides regionally with remotely-sensed imagery; 2. How do river networks adjust to an influx of landslide-derived sediment? by measuring channel aggradation/erosion patterns with repeat drone-based topographic surveys and direct tracking of coarse sediment transport using time-lapse images of channels downstream of landslide areas; and 3. What is the residence time of landslide-derived sediment in a tropical landscape? by repeated measurement of cosmogenic radionuclide concentrations in river sediment to detect changes in the flux of landslide-derived sediment over the following year.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.

从9月18日至20日，2022年，菲奥娜飓风向波多黎各岛提供了64厘米以上的降雨。这种过多的降水导致整个岛上的质量浪费和洪水，类似于玛丽亚飓风在2017年的影响。这两项事件均代表着研究热带气旋对高浮雕，热带景观进化的影响。该项目将支持两种科学家和设备的部署，以从波多黎各南部的两个集水区收集时间敏感和易腐的数据，受到飓风后大规模浪费的强烈影响。研究人员将使用这些流域作为模型研究区域：1。使用基于无人机的结构摄影的结构摄影调查滑坡沉积物，疤痕和后河流聚集的地形； 2。收集滑坡区域下游的河流沉积物样品，用于晶粒尺寸分析和宇宙核核追踪，界面滑坡衍生的沉积物，3。监测和记录仍然不稳定的滑坡的运动，并用延时摄像头积极地聚集河道。该项目将与位于波多黎各的共同投资者合作，并与联邦和地方科学家协同协调，从事危害评估和预防。现场工作部署将至少参与3名毕业生和3名本科生。六十多年来，地质学家辩论了大型但不经常的风暴事件对侵蚀景观的长期演变的贡献。对于热带周期等大风暴，直接对热带景观的地貌影响可能很明显：大规模浪费和洪水。但是，热带景观对暴风雨事件的扩展反应通常更为复杂，景观响应的测量需要在暴风雨事件发生后立即在集水区进行重复观察。该项目支持收集时间敏感和易腐的数据，以探讨有关热带景观对热带旋风引起的山体滑坡和洪水的反应的三个假设。具体来说，调查人员将解决以下问题：1。风暴事件在哪里（以及为什么）破坏山坡的稳定？通过调查滑坡疤痕和亲自沉积，通过延时摄像机监测静止不动的山坡，并用远程感知的图像在区域上绘制滑坡； 2。河网络如何适应滑坡衍生的沉积物的影响？通过通过重复基于无人机的地形调查来测量通道聚集/侵蚀模式，并使用滑坡区域下游的通道的延时图像直接跟踪粗沉积物传输；和3。在热带景观中，滑坡衍生的沉积物的停留时间是什么？通过重复测量河流沉积物中宇宙性放射线浓度的浓度，以检测次年在山体滑坡衍生的沉积物的通量变化。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来通过评估来诚实地通过评估来诚实地支持。