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: 2146640
• 负责人: Victor Tsai
• 金额: $ 32.47万
• 依托单位: Brown University
• 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: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2146640&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.

地震无处不在的自然灾害，在全球范围内脆弱的人口差异。对弱势结构的缓解措施也支持，并通过有针对性的外展活动为传统上的群体提供研究，该项目将使来自各种社会经济的经验范围传统上，物理和频率地面动作是根据摩擦模型来浮出水面的，该模型使摩擦过程在滑移期间的摩擦过程确定了诸如应力下降SE的经典摩擦模型，解释了在高频基础运动中观察到的许多方面天然。辐射模式，摩擦模型和影响模型的S波与P波辐射的比率使我们对地震破裂的理解有许多影响。为了使地震估计值估算的准确地面运动所需的断层区结构的测量值，地球上的波浪散射程度将通过使用未来的危险范围来提供crucil servactional offication。基金会的智力优点和更广泛的影响审查标准。