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.

EAR-0001132南加州大学 1999 年加利福尼亚州 M7.1 赫克托矿发生的地震为捕获断层带导波提供了绝佳的场所。 主震发生后 3 天，由 USGS 协调，我们在震中附近的地表破裂处部署了 PASSCAL 60 通道 GEOMETRICS 记录仪地震阵列，并在 10 天内记录了约 800 次余震。 数据显示，在破裂带内发生的事件中，靠近地表破裂的站点处有 4-6 Hz 断层带陷波。 随后，SCEC 在破裂区的 2 个地点部署了 83 台 PASSCAL REFTEK。 4 周内记录了约 2000 次余震。 我们建议对断层带陷波数据进行系统分析和FD-FE建模，以获取有关破裂带内部结构、断层分段的物理性质、断层带结构与动态破裂过程之间关系的更多信息就像大地震后断层的愈合一样。 该提案的主要任务是： 1. 3D 描绘断层带的物理性质和精细结构。 2. 利用爆炸重复进行地震勘测，以监测断层愈合情况。 3.通过以陷波为特征的断层跨距模拟破裂，评估破裂过程中断层带的破裂速度变化、滑移程度、动态应力和非线性能量耗散，以更好地了解损伤机制、断层摩擦和流变学。 4. 分析剪切波分裂以获得有关破裂区周围应力状态和破裂基质的附加信息。