EAR PF: Investigating the competition between thermal pressurization and dilatancy on rough surfaces at earthquake slip rates

EAR PF：研究地震滑移率下粗糙表面上热加压和剪胀之间的竞争

• 批准号: 2052897
• 负责人: Monica Barbery
• 金额: $ 17.4万
• 依托单位: Barbery, Monica R
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052897&HistoricalAwards=false
• 关键词: EAR; PF; Investigating; competition; between

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).An NSF EAR Postdoctoral Fellowship has been awarded to Dr. Monica Barbery to investigate earthquake physics at Brown University under the mentorship of Dr. Terry Tullis. Dr. Barbery will work to understand how rocks behave when exposed to the friction produced when there is rapid movement on a fault. The postdoctoral fellow will use new experimental machinery to conduct the first rock friction experiments at the velocity and pressures of real earthquakes to understand earthquake processes and the associated risks. This work will improve the ability to scale existing laboratory results to nature. This research will help in the development and modification of new and existing earthquake models that play a vital role in mitigating earthquake risk. In addition to these research activities, Dr. Barbery will work with Providence public schools to develop and implement curriculum for an educational outreach program at Brown University and will co-teach a stacked graduate and undergraduate course within the Department of Earth, Environmental, and Planetary Sciences.Dynamic weakening by thermal pore fluid pressurization (TP) and dynamic strengthening by dilatancy hardening (DH) are mechanisms theorized to contribute to the frictional strength and stability of faults during earthquakes. TP occurs as frictionally heated pore fluids expand along undrained faults to frictionally weaken the fault. DH occurs as microcracks develop during shearing and as previously mated fault surfaces become unmated with slip, both of which increase pore space and frictionally strengthen the fault. Both processes are closely tied to the roughness and displacement history of the sliding surface however TP will only contribute significantly to the frictional weakening that leads to earthquake instability if DH is minimal. Rock friction experiments will be conducted to examine the efficacy of TP and DH at elevated slip rates (≥100 mm/s), elevated confining pressure (≥25 MPa), and elevated pore pressure (≥25 MPa) using a newly modified rotary shear apparatus. Experiment results will be combined with modelling to characterize the competition between TP and DH across a range of slip rate, roughness, and displacement scales to better understand how to scale DH and TP processes to earthquakes on natural faults.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.

该奖项的全部或部分资金根据《2021 年美国救援计划法案》（公法 117-2）提供。 NSF EAR 博士后奖学金已授予 Monica Barbery 博士，在布朗大学博士的指导下研究地震物理学特里·巴伯里博士将致力于了解岩石在断层快速运动时的表现，该博士后研究员将使用新的实验机械以一定的速度进行首次岩石摩擦实验。这项工作将提高将现有实验室结果应用于自然的能力。这项研究将有助于开发和修改新的和现有的地震模型，这些模型在减轻地震方面发挥着至关重要的作用。除了这些研究活动之外，巴伯里博士还将与普罗维登斯公立学校合作，为布朗大学的教育推广计划开发和实施课程，并将在地球、环境、环境系内共同教授研究生和本科生课程。和行星科学。热动力减弱孔隙流体加压（TP）和剪胀硬化动态强化（DH）是理论上有助于地震期间断层摩擦强度和稳定性的机制，因为摩擦加热的孔隙流体沿着不排水断层膨胀，从而摩擦削弱了断层。随着剪切过程中微裂纹的形成以及先前配合的断层表面因滑移而脱离，这两者都会增加孔隙空间并增强断层的摩擦力，这两个过程都与粗糙度和摩擦力密切相关。然而，如果 DH 最小，则 TP 只会对导致地震不稳定的摩擦减弱产生显着影响，将进行岩石摩擦实验来检查 TP 和 DH 在高滑动速率（≥100 mm/s）下的功效。 ）、升高围压（≥25 MPa）和升高孔隙压力（≥25 MPa），使用新改进的旋转剪切装置将实验结果与建模相结合，以表征 TP 和 DH 在一系列滑移范围内的竞争。率、粗糙度和位移尺度，以更好地了解如何将 DH 和 TP 过程扩展到自然断层上的地震。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。