Collaborative Research: The Southern San Andreas Fault Zone Experiment

合作研究：南圣安地列斯断裂带实验

• 批准号: 1841315
• 负责人: Yehuda Ben-Zion
• 金额: $ 26.73万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1841315&HistoricalAwards=false
• 关键词: Collaborative; Research; Southern; San; Andreas; Collaborative; Research; Southern; San; Andreas

The San Andreas Fault (SAF) in California is a mature plate boundary fault capable of great (magnitude 8 or greater) earthquakes. The southern section of the SAF has not produced a major earthquake in historic times (over the last 300 years), and is currently believed to pose the largest seismic risk in California. This project will use new seismic and geodetic observations to investigate the sub-surface structure and geometry of the Southern San Andreas Fault (SSAF). In particular, the project will test a hypothesis that the SSAF may not be vertical and may substantial dip to the East. If confirmed, a non-vertical fault dip would have important implications for the mechanics and the long-term tectonic evolution of the SSAF. Better knowledge of the sub-surface geometry of the SSAF will also improve predictions of seismic radiation patterns and the intensity of ground shaking due to future large earthquakes on the SSAF. The broader impacts of this work will be refined estimates of seismic hazard in densely populated areas in Southern California and Mexico as well as support for the education of two graduate students.The researchers from this joint project between the University of California San Diego, Scripps Institution of Oceanography and the University of Southern California, will investigate the fault attitude at depth by imaging a low-rigidity damage zone and/or a bi-material interface associated with the SSAF in the upper crust. This will be accomplished by deploying a dense seismic array spanning the SSAF. Data from the deployed seismic array and regional seismic networks will be used to generate high-resolution tomographic images of the fault zone throughout the seismogenic layer. Seismic data will be combined with high-resolution geodetic observations, including Interferometric Synthetic Aperture Radar (InSAR) and Global Navigation Satellite System (GNSS). A joint analysis of seismic and geodetic data will provide new insights into the spatial extent and degree of damage around a mature plate boundary fault and enable comparisons with observations from other faults in California and elsewhere to examine how the distribution and amount of damage might depend on the fault age, seismic potential, and geometric complexity. The deployment of co-located dense seismic and geodetic arrays will establish a baseline for future measurements of possible time-dependent variations in mechanical properties of rocks comprising the fault zone due to external stress perturbations, which may help constrain the magnitude of absolute stress at seismogenic depth.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.

加利福尼亚州的San Andreas断层（SAF）是一个成熟的板边界断层，能够发生巨大（8或更大）地震。 SAF的南部地区在历史时期（在过去300年中）没有造成重大地震，目前被认为是加利福尼亚州最大的地震风险。该项目将使用新的地震和大地测量观测来研究南安德烈亚斯南部断层（SSAF）的地下结构和几何形状。特别是，该项目将检验一个假设，即SSAF可能不是垂直的，并且可能对东方进行大量倾斜。如果得到证实，非垂直断层倾角将对SSAF的力学和长期构造演变具有重要意义。更好地了解SSAF的地下几何形状还将改善地震辐射模式的预测以及由于SSAF上未来大型地震而引起的地面震动强度。这项工作的更广泛的影响将进行完善的估计，对南加州和墨西哥的人口稠密地区的地震危险估计值，并支持两名研究生的教育。加利福尼亚州圣地亚哥，斯克里普斯大学海洋学和南加州大学之间的联合项目的研究人员将通过与损害损害的界面相关联，并将其造成损害的态度，并将其造成损害的损害，或者是损害损害的界面。地壳。这将通过部署横跨SSAF的密集地震阵列来实现。来自部署的地震阵列和区域地震网络的数据将用于在整个地震层中生成断层区域的高分辨率断层图像。地震数据将与高分辨率的测量观测相结合，包括干涉合成孔径雷达（INSAR）和全球导航卫星系统（GNSS）。对地震和地震数据的联合分析将为成熟板边界断层周围的空间程度和损害程度提供新的见解，并可以将加利福尼亚和其他地方的其他断层的观察结果进行比较，以研究损害的分布和损失可能如何取决于断层年龄，西震势和几何势和几何复杂性。共同建立的密集地震和地球阵列的部署将建立一个基准，以未来测量可能与时间相关的岩石机械性能变化，该岩石的机械性能因外部压力扰动而构成断层区域的机械性能，这可能有助于限制通过Interniqual deem deem deem deem deem的构建，这可能会限制绝对压力的幅度更广泛的影响审查标准。