Postdoctoral Fellowship: EAR-PF: Does topographic stress connect subsurface to surface through influencing bedrock strength, clast size, and landslides?

博士后奖学金：EAR-PF：地形应力是否通过影响基岩强度、碎屑尺寸和山体滑坡将地下与地表连接起来？

• 批准号: 2305448
• 负责人: Justin Higa
• 金额: $ 18万
• 依托单位: Higa, Justin T
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305448&HistoricalAwards=false
• 关键词: Postdoctoral; Fellowship; EAR; PF; Does; Postdoctoral; Fellowship; EAR; PF; Does

Dr. Justin Higa has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities under the mentorship of Dr. Scott Rowland at the University of Hawaiʻi at Mānoa. Dr. Higa will examine the effects of topographic stress weathering in the valleys of Mt. Kahālāwai, Maui, Hawaiʻi, USA. Landslides from rocky, fractured mountains are deadly natural disasters that kill thousands of people every year. Research suggests that the shape of the land surface, the topography, can alter stresses within mountains to create some of these fractures and may help cause landslides. This process, called topographic stress weathering, is a budding frontier for understanding how fractures form in mountains. These fractures may weaken rock and generate fragments of rock that fall from steep slopes and collect in streams. Thus, there is a need to study whether topographic stress weathering is a major or minor contribution to the number and size of dangerous landslides on a mountain. Comparing calculations of topographic stress to rock strength, the size of rock fragments in streams, and mapped landslides may show how topographic stress weathering might affect landslide hazards. This project is important because it presents a new way to study natural disasters by linking topographic stress with field observations. Scientists can use such information to help protect people from landslides. Higa aims to engage with landowners and stakeholders of Mt. Kahālāwai to understand how this research can benefit local communities. Higa will also use this project to partner with Earth science students and help train a geologic workforce for the next generation of natural hazard scientists in Hawaiʻi.Recent studies on topographic stress weathering target how subsurface stress fields affect the extent and width of bedrock fractures. However, it remains unclear if topographic stresses are a major control of surface processes and natural hazards, such as landslides. This project will attempt to understand the relative contributions of topographic stress weathering versus climate in the generation of fractured rock and landslides. Previous work suggests that steep, narrow valleys concentrate fracture-inducing topographic stress perturbations at valley bottoms, whereas wider valleys may have such perturbations over larger areas. The study here will build off such work and focus on the valleys of an extinct volcano, Mt. Kahālāwai (also known as the West Maui Mountains), characterized by narrow and wide valleys with steep walls, a strong orographic rainfall gradient, and a lack of regional tectonic activity. First, a boundary element computer model will be used to predict the spatial distribution of topographic stresses within valleys of various morphologies (i.e., narrow or wide) and climates (i.e., windward or leeward). Next, researchers will collect (1) rebound hammer strength measurements of exposed bedrock, (2) size distributions of stream clasts, and (3) satellite mapping of landslides over decadal timescales from these valleys. If topographic stress controls surface processes, wide valleys may have weaker rocks, smaller clasts, and more landslides than steep, narrow valleys in similar climates. Then, comparing models and observations from valleys of similar morphologies but different climates will classify the effect of precipitation on weathering. Together, these tests will examine how topographic stress and climate work to erode steep valleys. Determining connections between topographic stress and geomorphic transport processes will help quantify the impact of stress-induced fracturing on various landscape evolution problems, which researchers can implement worldwide. Thus, this project may showcase a globally applicable method for examining weathering, erosion, and landslide hazards by establishing a framework linking topographic stress weathering and field observations.This project is jointly funded by the Division of Earth Science Postdoctoral Fellowship Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.

贾斯汀·希加（Justin Higa）博士被授予NSF地球科学博士后奖学金，以在夏威夷大学的夏威夷大学斯科特·罗兰德（Scott Rowland）的心态下进行研究和专业发展活动。 Higa博士将检查地形应力风化的影响，在美国夏威夷毛伊岛的Kahālāwai山谷中。来自洛矶山脉的山地滑坡是致命的自然灾害，每年杀死数千人。研究表明，陆地表面的形状，地形可以改变山内的压力，以创建其中一些碎片，并可能有助于引起滑坡。这个称为地形压力风化的过程是理解山区碎片的形成方式的崭露头角。这些碎片可能会削弱岩石并产生岩石碎片的碎片，这些岩石从钢槽中掉落并在溪流中收集。这就是需要研究地形压力风化是对山上危险滑坡的数量和大小的主要还是较小的贡献。比较地形应力与岩石强度的计算，溪流中的岩石碎片的大小以及绘图的滑坡可能会显示地形应力风化如何影响滑坡危险。该项目很重要，因为它通过将地形压力与现场观察联系起来，提出了一种研究自然灾害的新方法。科学家可以使用这些信息来帮助保护人们免受滑坡。 Higa的目标是与Kahālāwai山的土地所有者和利益相关者互动，以了解这项研究如何使当地社区受益。 Higa还将使用该项目与地球科学专业的学生合作，并帮助培训夏威夷下一代自然危害科学家的地质劳动力。关于地形应力风化的研究对地下压力场的影响如何影响基岩骨折的程度和宽度。但是，目前尚不清楚地形应力是否是表面过程和自然危害（例如滑坡）的主要控制。该项目将尝试了解地形应力风化与气候破裂的岩石和滑坡的相对贡献。先前的工作表明，陡峭，狭窄的山谷浓缩裂缝诱导的裂缝底部的地形应力扰动，而宽的山谷可能在较大的区域内具有这种扰动。此处的研究将建立此类工作，并专注于灭绝的火山的山谷，山（Kahālāwai）山（也称为西毛伊山山），其特征是狭窄和宽阔的山谷，具有钢墙，强大的地形降雨梯度，缺乏区域构造活动。首先，边界元素计算机模型将用于预测各种形态（即狭窄或宽）和气候（即迎风或左风）的山谷内地形应力的空间分布。接下来，研究人员将收集（1）弹性基岩，（2）溪流经典尺寸分布以及（3）在这些山谷中十年时间尺度上的滑坡的卫星图。如果地形应力控制地表过程，那么在类似气候下，宽山谷可能具有较弱的岩石，较小的经典和山体滑坡。然后，比较类似形态但不同攀登的山谷的模型和观察结果将对降水对风化的影响进行分类。这些测试将共同研究地形压力和气候工作如何侵蚀陡峭的山谷。确定地形压力与地貌交通工具之间的联系将有助于量化压力引起的破裂对各种景观演化问题的影响，研究人员可以在全球实施这些景观进化问题。该项目可以通过建立一个框架，将地形压力风化和现场观察联系起来，通过建立一个框架来研究全球适用的方法，用于检查风化，侵蚀和滑坡危害。该项目由地球科学科学博士后奖学金计划和既定的计划（通过启发竞争性的研究）进行了支持（EPSCOR）。基金会的智力优点和更广泛的影响审查标准。