Study of the Internal Structure, Dynamic Rupture, and Post-Earthquake Healing of the Hector Mine Earthquake Rupture Zone Using Fault-Zone Trapped Waves

利用断层带陷波研究赫克托矿地震破裂带的内部结构、动态破裂及震后修复

• 批准号: 0001132
• 负责人: Yong-Gang Li
• 金额: $ 26.32万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0001132&HistoricalAwards=false
• 关键词: Study; Internal; Structure; Dynamic; Rupture

EAR-0001132University of Southern CaliforniaThe M7.1 Hector Mine, California, earthquake in 1999 provides an excellent site for capture of fault-zone guided waves. 3 days after the mainshock coordinated by the USGS, we deployed a seismic array of a 60-channel GEOMETRICS recorder from PASSCAL across the surface rupture near the epicenter and recorded ~800 aftershocks in 10 days. The data show 4-6 Hz fault-zone trapped waves at stations close to the surface rupture for events occurring within the rupture zone. Afterwards, the SCEC organized a deployment of 83 PASSCAL REFTEKs at 2 sites on the rupture zones. ~2000 aftershocks were recorded in 4 weeks. We propose to do a systematic analysis and FD-FE modeling of fault-zone trapped wave data for more information about the internal structure of the rupture zone, physical nature of fault segmentation, the relationship between the fault zone structure and dynamic rupture process as well as the healing of the fault after a major earthquake. The main tasks of this proposal are: 1. To delineate the physical properties and fine structure of the fault zone in 3-D. 2. to repeat seismic surveys using explosions for monitoring the fault healing. 3. to simulate the rupture through the fault stepovers characterized by trapped waves, and assess the rupture velocity variations, extent of slip, dynamics stresses and nonlinear energy dissipation in the fault zone during the rupture for a better understanding the damage mechanism, fault friction and rheology. 4. to analyse shear-wave splitting for additional information on the stress state and fracture matrix around the rupture zone.

南加州大学1999年加利福尼亚州赫克托尔矿发生的7.1级地震为断层带引导波的捕捉提供了一个绝佳的地点。在美国地质勘探局的协调下，主震发生3天后，我们从帕斯卡尔部署了一个60通道的几何记录仪阵列，穿过震中附近的地表破裂，在10天内记录了约800次余震。数据显示，对于发生在破裂带内的事件，在接近地表破裂的台站出现了4-6 Hz的断层带捕获波。之后，SCEC在破裂带的2个地点组织了83个帕斯卡尔reftek的部署。4周内发生了约2000次余震。我们建议对断裂带陷波数据进行系统分析和FD-FE建模，以进一步了解断裂带的内部结构、断层分割的物理性质、断裂带结构与动态破裂过程的关系以及大地震后断层的愈合情况。本提案的主要任务是：1。三维圈定断裂带的物理性质和精细构造。2. 用爆炸重复地震调查以监测断层愈合。3. 模拟以陷波为特征的断裂带的破裂过程，评估断裂过程中断裂带的破裂速度变化、滑移程度、动应力和非线性能量耗散，以更好地了解断裂的破坏机制、断层摩擦和流变学。4. 分析剪切波分裂，以获得有关破裂带周围应力状态和破裂基质的附加信息。