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

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.

Justin Higa博士获得了NSF地球科学博士后奖学金，在夏威夷大学马诺阿分校Scott Rowland博士的指导下开展研究和专业发展活动。Higa博士将研究地形应力风化在山的山谷的影响。关闭MT，USA.来自多岩石、断裂的山脉的山体滑坡是致命的自然灾害，每年造成数千人死亡。研究表明，陆地表面的形状，地形，可以改变山脉内部的应力，从而产生一些裂缝，并可能导致山体滑坡。这个过程被称为地形应力风化，是理解山脉中裂缝如何形成的一个新兴前沿。这些裂缝可能会削弱岩石，并产生岩石碎片，这些碎片从陡峭的斜坡上掉落并聚集在溪流中。因此，有必要研究地形应力风化是否是一个主要或次要的贡献的数量和规模的危险山体滑坡。比较地形应力与岩石强度、溪流中岩石碎片的大小以及绘制的滑坡的计算结果，可以显示地形应力风化可能如何影响滑坡灾害。这个项目很重要，因为它提出了一种新的方法来研究自然灾害，将地形应力与实地观察联系起来。科学家可以利用这些信息来帮助保护人们免受山体滑坡的影响。Higa旨在与Mt.的土地所有者和利益相关者进行接触。Kahālāwai了解这项研究如何使当地社区受益。Higa还将利用该项目与地球科学专业的学生合作，并帮助为夏威夷的下一代自然灾害科学家培训地质工作人员。最近关于地形应力风化的研究针对地下应力场如何影响基岩裂缝的范围和宽度。然而，目前尚不清楚地形应力是否是地表过程和自然灾害（如滑坡）的主要控制因素。本项目将试图了解地形应力风化与气候在产生断裂岩石和滑坡中的相对作用。以前的工作表明，陡峭，狭窄的山谷集中在谷底的地形应力扰动，而较宽的山谷可能有这样的扰动在更大的地区。这里的研究将建立在这样的工作基础上，并集中在一个死火山的山谷，山。卡哈拉威（Kahālāwai，也被称为西毛伊岛山脉），其特点是狭窄而宽阔的山谷，陡峭的墙壁，强烈的地形降雨梯度，以及缺乏区域构造活动。首先，边界元计算机模型将用于预测各种形态的山谷内的地形应力的空间分布（即，窄或宽）和气候（即，迎风或背风）。接下来，研究人员将收集（1）暴露基岩的回弹锤强度测量值，（2）溪流碎屑的大小分布，以及（3）这些山谷数十年时间尺度上滑坡的卫星地图。如果地形应力控制了表面过程，那么在类似气候下，宽阔的山谷可能比陡峭、狭窄的山谷拥有更脆弱的岩石、更小的碎屑和更多的山体滑坡。然后，比较模型和观测相似的形态，但不同的气候山谷将分类降水对风化的影响。这些测试将共同研究地形应力和气候如何侵蚀陡峭的山谷。确定地形应力和地貌输运过程之间的联系将有助于量化应力引起的断裂对各种景观演化问题的影响，研究人员可以在全球范围内实施。因此，该项目可以展示一种全球适用的方法，用于检查风化，侵蚀，该项目由地球科学部博士后研究计划和促进竞争性研究既定计划（EPSCoR）联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。