Toward physics-based seismic hazard assessments: A holistic approach to understanding the physics of induced earthquakes

基于物理的地震灾害评估：理解诱发地震物理的整体方法

• 批准号: RGPIN-2019-06482
• 负责人: Lui, SemechahKY
• 金额: $ 2.19万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738934
• 关键词: Toward; physics; based; seismic; hazard

Earthquakes, which result from the movements of faults in the subsurface, are of scientific and societal interest due to their destructive potential. Because of the abrupt and complex nature of the dynamic process, as well as the opacity of the deforming crust, it remains a challenge to obtain a comprehensive, physics-based understanding of earthquakes. In particular, seismicity that points to an anthropogenic origin is becoming the focus of scientific and political discussions, with multiple published studies suggesting its correlation with fluid-injection activities associated with unconventional hydrocarbon production and geothermal energy. This is a pressing issue, because many induced earthquakes occur in populated regions that are considered seismically dormant and unprepared for any form of strong shaking. At present, the underlying physical mechanisms of induced earthquakes remain elusive and current seismic hazard maps rely mostly on statistical analyses of existing earthquake catalogues. A quantitative predictive model requires deeper investigation into the physics of induced earthquakes. My research program is to advance the understanding of seismic source processes and fault rupture dynamics, with a primary focus on induced seismicity. Recent advancements in seismic instrumentations and high-performance computing have allowed geoscientists to strive toward a more profound and practical understanding to earthquakes. In the next five years, we will address several key issues: (1) Characterizing the role of injection and frictional parameters in earthquake triggering, (2) Illuminating features of the host geological environment, (3) Modeling of the triggered ground motions, (4) Quantifying the effect of different possible triggering mechanisms on induced seismicity, (5) Characterizing the interplay of seismic and aseismic slip in long-term earthquake cycles. The research will be innovative and distinct among induced seismicity studies by taking a holistic approach that investigates induced seismicity at multiple scales and from multiple angles by combining field observations, laboratory experiments, and computational modeling. The characterization of seismic sources through observables (field and lab data) will serve as the basis for constructing realistic physically-based predictive models with state-of-the-art numerical tools. The numerical models we use are governed by sophisticated empirical friction laws and will bridge the gap among seismic observations at various scales, bringing a comprehensive understanding to the physics of induced earthquakes. Through international collaborations with seismologists and rock engineers, my program will contribute to improving hazard mitigation and to formulating clear industry regulations and investment strategies. Advancing the science of induced seismicity will also make significant contributions to our knowledge of large-magnitude earthquake nucleation and triggering in natural earthquakes.

地震是由地下断层运动引起的，由于其潜在的破坏性而引起科学和社会的关注。由于动态过程的突然性和复杂性，以及变形地壳的不透明性，对地震获得全面的、基于物理的理解仍然是一个挑战。特别是，指向人为起源的地震活动正在成为科学和政治讨论的焦点，多项已发表的研究表明其与非常规碳氢化合物生产和地热能相关的流体注入活动的相关性。这是一个紧迫的问题，因为许多诱发地震发生在人口稠密的地区，这些地区被认为处于地震休眠状态，对任何形式的强烈震动没有做好准备。目前，诱发地震的潜在物理机制仍然难以捉摸，当前的地震灾害图主要依赖于现有地震目录的统计分析。定量预测模型需要对诱发地震的物理学进行更深入的研究。我的研究计划是增进对震源过程和断层破裂动力学的理解，主要关注诱发地震活动。地震仪器和高性能计算的最新进展使地球科学家能够努力对地震有更深刻、更实际的理解。在未来五年中，我们将解决几个关键问题：（1）表征注入和摩擦参数在地震触发中的作用，（2）阐明主地质环境的特征，（3）触发的地面运动建模，（ 4）量化不同可能的触发机制对诱发地震活动的影响，（5）表征长期地震周期中地震和地震滑移的相互作用。该研究将采用整体方法，结合现场观测、实验室实验和计算模型，在多个尺度和多个角度研究诱发地震活动，从而在诱发地震活动研究中具有创新性和独特性。通过可观测数据（现场和实验室数据）对震源进行表征将成为使用最先进的数值工具构建现实的基于物理的预测模型的基础。我们使用的数值模型受复杂的经验摩擦定律控制，并将弥合不同尺度地震观测之间的差距，从而全面了解诱发地震的物理学。通过与地震学家和岩石工程师的国际合作，我的项目将有助于改善减灾并制定明确的行业法规和投资策略。推进诱发地震活动科学也将为我们对自然地震中大震级地震成核和触发的了解做出重大贡献。