Collaborative Proposal: Testing Collision Versus Frictional Stress-Drop Models of High-Frequency Earthquake Ground Motions

合作提案：测试高频地震地面运动的碰撞与摩擦应力降模型

• 批准号: 2231705
• 负责人: Daniel Trugman
• 金额: $ 31.31万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2231705&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Testing; Collision; Versus

Earthquakes are ubiquitous natural hazards that impact vulnerable populations near active fault systems across the globe. Despite longstanding and intensive research by the scientific community, several key aspects of the earthquake rupture process remain poorly understood. This project focuses on understanding the physical origin of the high-frequency seismic energy that is generated during the rupture process as earthquake faults slip past one another. These advances in scientific understanding have broad implications for earthquake hazard mitigation, informing how future building design codes should be constructed in order to prevent earthquake damage to vulnerable structures. The project also supports early career scientists and provides research opportunities to traditionally underrepresented groups in the geosciences. Through targeted outreach efforts, the project will engage high school students from a diverse range of socioeconomic backgrounds, with an aim toward experiential learning that will guide them in their future careers.The physical origins for high-frequency ground motions have traditionally been explained in terms of a frictional model that postulates that frictional processes during fault slip determine rupture properties like stress drop, which in turn control shaking amplitudes. However, these classical frictional models often struggle to explain many aspects of the high-frequency ground motions observed in nature. This discrepancy has led to the hypothesis that elastic impacts of fault-zone structures that occur to accommodate the geometric complexity of fault systems may play an important role in the generation of high-frequency ground motions. The project will explicitly test this hypothesis using three sets of seismological observations – corner frequencies, radiation patterns, and the ratio of S-wave to P-wave radiated energy – for which the frictional and impact models make distinctly different predictions. This work has a number of important implications for our understanding of the physics of earthquake rupture, including determining the degree to which detailed measurements of fault zone structure are needed to make accurate ground motion predictions, revising the physical interpretation of seismological stress drop estimates, and constraining the degree of wave scattering in the Earth’s crust. These advances, taken holistically, will provide crucial observational constraints for future earthquake hazard mitigation efforts.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.

地震是影响全球活动断层系统附近脆弱人群的普遍自然灾害，尽管科学界进行了长期深入的研究，但对地震破裂过程的几个关键方面仍然知之甚少。地震断层相互滑过时破裂过程中产生的频率地震能量这些科学认识的进步对减轻地震灾害具有广泛的影响，告知未来的建筑设计规范应如何制定，以防止地震对脆弱结构造成损害。 。该项目还支持早期职业科学家，并为地球科学领域传统上代表性不足的群体提供研究机会，该项目将吸引来自不同社会经济背景的高中生，旨在引导他们进行体验式学习。传统上，高频地面运动的物理起源是用摩擦模型来解释的，该模型假设断层滑动过程中的摩擦过程决定了应力降等破裂特性，从而控制了震动幅度。型号人们常常很难解释自然界中观察到的高频地面运动的许多方面，这种差异导致了这样的假设：为适应断层系统的几何复杂性而发生的断层带结构的弹性影响可能在生成中发挥重要作用。该项目将使用三组地震观测数据（角频率、辐射模式以及横波与纵波辐射能量之比）明确检验这一假设，摩擦和冲击模型对此做出了明确的解释。这项工作有不同的预测。对我们理解地震破裂物理学有许多重要影响，包括确定需要对断层带结构进行详细测量以进行准确的地面运动预测的程度，修改地震应力降估计的物理解释，以及限制程度总体而言，这些进展将为未来减轻地震灾害的努力提供重要的观测约束。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进行评估，被认为值得支持。标准。

项目成果

Fault Roughness at Seismogenic Depths and Links to Earthquake Behavior

发震深度的断层粗糙度及其与地震行为的联系

• DOI: 10.1785/0320220043
• 发表时间: 2023-01
• 期刊: The Seismic Record
• 作者: Cochran, Elizabeth S.;Page, Morgan T.;van der Elst, Nicholas J.;Ross, Zachary E.;Trugman, Daniel T.
• 通讯作者: Trugman, Daniel T.

The Rocks That Did Not Fall: A Multidisciplinary Analysis of Near‐Source Ground Motions From an Active Normal Fault

没有掉落的岩石：对活动正断层近源地震动的多学科分析

• DOI: 10.1029/2023av000885
• 发表时间: 2023-04
• 期刊: AGU Advances
• 影响因子: 8.4
• 作者: Trugman, D. T.;Brune, J.;Smith, K. D.;Louie, J. N.;Kent, G. M.
• 通讯作者: Kent, G. M.

Spectral Characteristics of Hydraulic Fracturing-Induced Seismicity Can Distinguish between Activation of Faults and Fractures

水力压裂诱发地震活动的频谱特征可以区分断层和裂缝的活动

• DOI: 10.1785/0220230024
• 发表时间: 2023-05-08
• 期刊: Seismological Research Letters
• 影响因子: 3.3
• 作者: N. Igonin;D. Trugman;Keyla Gonzalez;D. Eaton
• 通讯作者: D. Eaton