Recovery of Material Parameters and Friction Laws Associated with Earthquakes, Interseismic Slip, and Tidal Deformation

恢复与地震、震间滑移和潮汐变形相关的材料参数和摩擦定律

基本信息

批准号：
2108175
负责人：
Maarten de Hoop
金额：
$ 20.8万
依托单位：
William Marsh Rice University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108175&HistoricalAwards=false
关键词：
Recovery Material Parameters Friction Laws

项目摘要

The study of earthquake physics remains highly challenging because of its complex dynamics and multifaceted nature. This research takes on the challenge of mitigating the impacts of earthquakes through mathematical understanding. It holds the promise of producing fundamentally new insights in fault physics and advancing the knowledge of friction laws, nucleation and rupture dynamics, localization of (micro)seismicity, crustal rheology, and monitoring stress and material properties. Determining the friction during an earthquake is required to understand when and where earthquakes occur. While this case cannot be reasonably studied in isolation, it is a central thrust of the research. A study of earthquake physics comprises nonlinear (segmented) fault dynamics, formulated as an inverse problem. Faults have nontrivial geometry, dependent on material properties of juxtaposed crustal blocks changing in time, stress, and general rheology of Earth’s crust and upper mantle and large-scale deformation. Tidal forcing will be exploited to enable the study of buoyancy structure deep in our planet's interior. Results will yield procedures for monitoring and obtaining invaluable information about rheology and microstructure in the subsurface, which could also be employed in geothermal exploration and carbon dioxide sequestration. The project offers, via collaborations, a unique interdisciplinary educational experience for the students giving them a much broader appreciation of the importance of novel techniques and real-life implications. The investigator will study inverse problems associated with earthquakes, interseismic slip, and tidal deformation. These inverse problems are defined through systems of partial differential equations describing elastic-gravitational deformation and waves, coupled to nonlinear rate- and state-dependent friction laws on faults, as well as extensions to viscoelastic and nonlocal elastic behaviors accounting for microstructure and complex rheologies. The key advances will pertain to determining friction during an earthquake, gleaning information about friction laws on faults also during interseismic deformation, in conjunction with recovering anisotropic elastic / viscoelastic / nonlocal-elastic material parameters in the crust and fault zones exploiting ruptures, dislocation, and microseismic clouds as sources as well as tidal forcing of the Moon. The rigorous study of possible rapid recovery of a moment tensor (earthquake magnitude and focal mechanism for early warning) from prompt elastogravity signals will be included in the analysis.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.

由于其复杂的动力学和多方面的性质，地震物理学的研究仍然具有很高的挑战性，这项研究面临着通过数学理解减轻地震影响的挑战，它有望产生断层物理学的全新见解并推进断层物理学的知识。需要确定摩擦定律、成核和破裂动力学、（微）地震活动的定位、地壳流变学以及监测地震期间的摩擦力，以了解地震发生的时间和地点。单独合理地进行研究，它是地震物理学研究的核心，包括非线性（分段）断层动力学，将其表述为反问题，断层具有重要的几何形状，取决于并置地壳块的材料特性随时间的变化，将利用地壳和上地幔的一般流变学和大规模变形来研究地球内部深处的浮力结构。监测和获取有关地下流变学和微观结构的宝贵信息，这些信息也可用于地热勘探和二氧化碳封存。该项目通过合作为学生提供了独特的跨学科教育体验，让他们更广泛地认识到其重要性。研究人员将研究与地震、震间滑移和潮汐变形相关的反演问题，这些反演问题是通过描述弹性重力变形和潮汐变形的偏微分方程组来定义的。波，与断层上的非线性速率和状态相关的摩擦定律耦合，以及解释微观结构和复杂流变学的粘弹性和非局部弹性行为的扩展，关键进展将涉及地震期间的摩擦确定，收集有关摩擦定律的信息。还可以在震间变形期间对断层进行分析，同时利用破裂、位错和微震恢复地壳和断层带中的各向异性弹性/粘弹性/非局部弹性材料参数这项严格的研究反映了从即时弹重力信号中可能快速恢复力矩张量（地震震级和早期预警的震源机制）。该奖项是 NSF 的法定任务。通过使用基金会的智力优点和更广泛的影响审查标准进行评估，并被认为值得支持。