EAGER: Deciphering boulder movement history using cosmogenic isotopes - a numerical investigation.

EAGER：使用宇宙同位素破译巨石运动历史 - 一项数值研究。

• 批准号: 1204375
• 负责人: Michael Lamb
• 金额: $ 4.5万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-12-01 至 2012-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1204375&HistoricalAwards=false
• 关键词: EAGER; Deciphering; boulder; movement; history

We currently lack quantitative field metrics to decipher how often boulders move by fluvial or debris flow processes. This project aims to develop and run numerical experiments to test whether the frequency of boulder movement can be deciphered from cosmogenic exposure dating. Preliminary modeling has shown that, in some cases, the number of boulder movement events can be determined from the pattern of exposure around the circumference of a boulder. The proposed work would include systematic investigation of likely controlling variables (e.g., boulder size, erosion rate, and inheritance) on the mean and spatial variance in nuclide concentration around and within a mobile, eroding boulder. Results from this effort would form the backbone for future field sampling campaigns aimed at measuring boulder movement, potentially applicable to a wide range of environments (e.g., river channels, debris flow fans, moraines).Boulders line the beds of many rivers and are an important control on rates of landscape evolution, yet their long-term behavior is not well understood. The recurrence interval of large, boulder-mobilizing events is often beyond the historical record, leaving the probability of these events poorly constrained. The project aims to improve our ability to predict the frequency of boulder moving events for hazard mitigation and habitat restoration. It could potentially lead to the ability to quantify infrequent, large magnitude flood and debris flow events with recurrence intervals greater than ~ 1000 yrs, which can cause significant loss of life and property.

我们目前缺乏定量的现场指标来破译巨石通过河流或泥石流过程移动的频率。 该项目旨在开发和运行数值实验，以测试是否可以从宇宙成因暴露测年中破译巨石运动的频率。初步建模表明，在某些情况下，巨石运动事件的数量可以根据巨石圆周周围的暴露模式来确定。拟议的工作将包括系统研究可能的控制变量（例如，巨石大小、侵蚀率和继承性），这些变量对移动、侵蚀巨石周围和内部的核素浓度的平均值和空间方差进行研究。这项工作的结果将成为未来旨在测量巨石运动的现场采样活动的支柱，可能适用于广泛的环境（例如河道、泥石流扇、冰碛）。巨石排列在许多河流的河床上，是一种对景观演化速率的重要控制，但它们的长期行为尚不清楚。大型巨石动员事件的复发间隔往往超出历史记录，导致这些事件发生的概率很难受到限制。该项目旨在提高我们预测巨石移动事件频率的能力，以减轻灾害和恢复栖息地。它可能会导致能够量化罕见的、大规模的洪水和泥石流事件，这些事件的复发间隔大于约 1000 年，这些事件可能会造成重大的生命和财产损失。