Integration of the Physical and Chemical Rock Properties, Structure, and Permeability of the San Andreas Fault, San Andreas Fault Observatory at Depth Borehole, California

圣安德烈亚斯断层的物理和化学岩石特性、结构和渗透性的整合，加利福尼亚州深孔圣安德烈亚斯断层观测站

• 批准号: 1829465
• 负责人: Kelly Keighley Bradbury
• 金额: $ 23.41万
• 依托单位: Utah State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1829465&HistoricalAwards=false
• 关键词: Integration; Physical; Chemical; Rock; Properties

Ten years ago, about 40 m of whole rock core was collected from a depth of approximately 3 km across an actively creeping trace of the San Andreas Fault as part of Earthscope's San Andreas Fault Observatory at Depth Borehole. Every centimeter of SAFOD core sampled is extremely valuable and represents a rare view into an active plate boundary fault. The aim of the overall project is to provide more realistic constraints for earthquakes that occur along the San Andreas Fault and, more broadly, within active faults around the world through the examination of whole rock core samples and a synthesis of a variety of geological and geochemical data. Earthquakes occur as faults displace rocks in a response to stress within the Earth's crust. Before, during, and after an earthquake, the rocks record physical and chemical changes that are associated with this cycle. Earthquakes and associated hazards pose a significant risk to society that may result in loss of life, serious injuries, damage to infrastructure, and major economic impacts. This work contributes to the development of better constraints for earthquake ground-shaking and seismic safety hazard models for active fault systems. Working with undergraduate and graduate students, the project will create engaging and interactive learning modules for undergraduate non-majors and community-at-large events that contribute to the legacy of SAFOD and Earthscope data, and increase students' and the general public's awareness about the field of Earthquake Geology. This study is focused on the structure and composition of the San Andreas Fault at depth using the available range of cuttings, sidewall cores, whole-rock core, and downhole geophysical logging data from Earthscope's San Andreas Fault Observatory at Depth Borehole. Specifically, the proposed research aims to: 1) Examine the mechanisms of deformation and slip localization, the grain- to fault-scale nature of fluid-rock interactions within the fault zone, and to determine the origin, nature, and roles of carbonaceous matter in the fault zone, testing the hypothesis that carbon-bearing fault rocks influence slip weakening and localization or serve as indicators for earthquake induced fluid migration.2) Couple new results on fault zone composition and structure with borehole-based data to determine the elastic properties of the fault zone, to examine the nature and significance of time-dependent chemical and physical fault zone processes, and to relate the material properties to key elastic parameters that affect the energy distributions in and near fault zones. 3) Synthesize and re-evaluate all published and accessible results by numerous research groups of the geology, geochemistry, and rock properties of SAFOD with our new results, to develop a predictive schematic model of fault zone structure and properties, which we will then relate to its elastic moduli. 4) Educate and mentor students to become competitive STEM Workforce members and effective science communicators through participation in research and in the development of interactive educational activities that contribute to the legacy of SAFOD and Earthscope data, and increasing students' and the general public's awareness of earthquake geology and seismic hazards. The SAFOD core provides an opportunity to rigorously examine in situ fault-rock samples in order to decipher the processes that influence seismic slip and aseismic creep. Systematic integration of microscopy and geochemistry enables us to understand structural diagenesis in dynamic, complex, and heterogeneous fault zones. Remnants of extensive alteration during fluid-rock interactions, and complex microstructural changes during deformation are difficult to resolve without diverse techniques at various scales. The proposed interdisciplinary approach using high-resolution microscopy, geochemistry, and evaluation of rock properties spans a wide range of scales and methods and will further contribute to our ability to decipher the physio-chemical processes (e.g., pressure, temperature, permeability, fluid composition and source) from processes associated with fluid migration at the microscopic scale in faults (e.g., thermal pressurization). The project will expand knowledge of the role of fluids during fault weakening, constrain the conditions associated with fluid migration at the micro-scale during the earthquake cycle, and determine the evolution of strength and slip behavior of major tectonic faults for seismic hazard assessment. The new and synthesized data sets will become accessible to the entire scientific community, as envisioned by the original Earthscope initiative and work towards answering one of Earthscope's outstanding questions identified in 2010: What is the slip distribution during earthquakes and what can we learn from heterogeneities about fault geometry and fault rheology?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.

十年前，作为Earthscope的San Andreas断层天文台的一部分，从大约3 km的深度中收集了大约40 m的整个摇滚芯。 SAFOD核心采样的每一厘米都非常有价值，并且代表了活动板边界故障的罕见视图。整个项目的目的是通过检查整个摇滚核心样本以及多种地质和地球化学数据的综合，为沿圣安德烈亚斯断层发生的地震提供了更现实的约束。地震发生时，断层会在地壳内的压力反应中置换岩石。地震之前，期间和之后，岩石记录与该周期相关的物理和化学变化。地震和相关危害对社会构成了重大风险，可能导致生命损失，严重伤害，对基础设施的损害以及重大的经济影响。这项工作有助于开发更好的限制地震地面震撼和地震安全风险模型，用于主动断层系统。该项目与本科生和研究生合作，将创建引人入胜且互动的学习模块，以促进本科生的非硕士和一般社区活动，从而有助于Safod和Earthscope数据的遗产，并提高学生以及将军公众对地震地质学领域的认识。这项研究的重点是使用可用的插条，侧壁芯，全摇滚核心和井下地球物理记录数据的San Andreas断层的结构和组成，并从Earthscope的San Andreas断层天文台处的深度钻孔进行了地球物理记录数据。 具体而言，拟议的研究的目的是：1）检查变形和滑动定位的机制，晶粒到断层区域内流体岩石相互作用的断层尺度性质，并确定断层区域中碳质物质的起源，性质，性质和作用具有基于钻孔的数据的结构，以确定断层区的弹性特性，检查时间依赖性化学和物理断层区域过程的性质和意义，并将材料特性与影响近乎断层区域能量分布的关键弹性参数相关联。 3）通过我们的新结果，综合和重新评估了Safod的地质，地球化学和岩石性能的许多研究小组的所有发布和可访问的结果，以开发出断层区结构和属性的预测示意性模型，然后我们将与其弹性模量有关。 4）教育和导师学生通过参与研究和发展互动式教育活动，成为竞争性的STEM劳动力成员和有效的科学沟通者，这些活动有助于Safod和Earthscope数据的遗产，并提高学生的学生以及公众对地震地震和地震危害的认识。 Safod核心提供了一个机会，可以严格检查原位断层摇滚样品，以破译影响地震滑动和无性敏捷的过程。显微镜和地球化学的系统整合使我们能够理解动态，复杂和异质断层区域中的结构成岩作用。在流体岩石相互作用期间发生广泛改变的残留物以及变形过程中复杂的微结构变化在没有各种尺度的各种技术的情况下很难解决。提出的跨学科方法使用高分辨率显微镜，地球化学和岩石性能的评估涵盖了广泛的尺度和方法，并将进一步有助于我们从与流体迁移相关的PRONID CRIPATION CARPARITIAD（CORPARITIAL PYRACTIAD）（e。该项目将扩大对断层弱化过程中流体作用的知识，限制地震周期中与微尺度上流体迁移相关的条件，并确定对地震危害评估的主要构造断层的强度和滑动行为的演变。正如原始的Earthscope倡议所设想的那样，整个科学界将可以访问新的和合成的数据集，并努力回答2010年地球景观的一个杰出问题之一：地震期间的滑动分布是什么，我们可以从异质性中学到什么，从而通过缺陷奖来评估NSF的构建奖，并依靠NSF的裁定，并表现出了NSF的构建，并且是DEEMET的价值，并且是deeme deeme deeme的价值，并且是依据的依据。更广泛的影响审查标准。