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Refining Seismic Velocity and Attenuation Structure of the San Andreas Fault Near Parkfield, California Using Full-3D Waveform Tomography

使用全 3D 波形断层扫描细化加利福尼亚州帕克菲尔德附近圣安德烈亚斯断层的地震速度和衰减结构

基本信息

批准号：
0944206
负责人：
Po Chen
金额：
$ 11.18万
依托单位：
University of Wyoming
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2010
资助国家：
美国
起止时间：
2010-07-15 至 2013-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944206&HistoricalAwards=false
关键词：
Refining Seismic Velocity Attenuation Structure

项目摘要

The PI will conduct full-3D waveform tomography (F3DT) for the seismic velocity and attenuation structure on the San Andreas Fault zone around the Parkfield area in California. In the F3DT algorithm, both the reference structural model and the derived model perturbations are all 3D in space and the full-wave sensitivity (Fréchet) kernels are calculated from the full physics of 3D wave propagation. Joint inversions will be carried out for both seismic velocity and attenuation structures of the San Andreas Fault Zone using waveform recordings from natural and/or man-made earthquakes. By integrating high-quality waveform data into the F3DT algorithm, they expect to substantially enhance both the resolution and the accuracy of the 3D seismic velocity and attenuation structure in the Parkfield area.Variations in physical properties of a fault zone may influence the generation, propagation and arrest of large earthquakes. Results from previous studies suggest that inelastic processes such as migration of fluids in fractures or microcracks and the associated changes in pore pressure and chemical effects such as stress corrosion and pressure solution may lead to mechanical failure and nucleation of earthquakes. Since attenuation structure is sensitive to fracturing, crack accumulation and partial saturation, the proposed high-resolution full-3D waveform tomography for fault-zone attenuation structure will provide important additional constraints to improve our understanding of fault-zone processes.This project is funded jointly by the EPSCoR, Earthscope and Geophysics programs.

PI 将对加利福尼亚州帕克菲尔德地区周围圣安德烈亚斯断层带的地震速度和衰减结构进行全 3D 波形断层扫描 (F3DT)。在 F3DT 算法中，参考结构模型和导出模型扰动都是空间中的 3D 扰动，并且全波灵敏度 (Fréchet) 内核是根据 3D 波传播的完整物理原理计算的。将使用自然和/或人为地震的波形记录对圣安德烈亚斯断层带的地震速度和衰减结构进行联合反演。通过将高质量波形数据集成到F3DT算法中，他们期望大幅提高Parkfield地区3D地震速度和衰减结构的分辨率和精度。断层带物理性质的变化可能会影响大地震的产生、传播和阻止。先前的研究结果表明，裂缝或微裂纹中流体迁移等非弹性过程以及相关的孔隙压力变化和应力腐蚀和压力溶解等化学效应可能导致机械破坏和地震成核。由于衰减结构对断裂、裂纹累积和部分饱和很敏感，因此所提出的断层带衰减结构高分辨率全3D波形层析成像技术将为提高我们对断层带过程的理解提供重要的附加约束。该项目由EPSCoR、Earthscope和地球物理项目联合资助。