Observations and Modeling of Shallow Fault Creep Along the San Andreas Fault Zone

圣安德烈亚斯断层带浅层断层蠕变的观测和模拟

• 批准号: 0811772
• 负责人: David Sandwell
• 金额: $ 29.8万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0811772&HistoricalAwards=false
• 关键词: Observations; Modeling; Shallow; Fault; Creep

Very precise measurements of ground motion are being used to study the distribution and magnitude of slow creep along faults of the San Andreas Fault (SAF) system. Measuring and modelling fault creep is improving our understanding of both earthquake hazard and earthquake physics. Much of the creep signal is close to the fault and therefore, best observed by a space-based technique called Interferometric Synthetic Aperture Radar (InSAR) because of its complete 50-m spatial resolution. The new aspect of this research is the use of L-band InSAR data from the recently launched ALOS spacecraft (JAXA). L-band interferogram remain coherent over longer time intervals than the previously available C-band interferograms. These new data are especially important in central and northern California where C-band permanent scattering methods are only partially successful in measuring slow crustal deformation. The three-year investigation includes the following tasks: (1) Participate in the Western North America InSAR consortium (WInSAR) to assemble the data needed for this investigation as well as to prepare for future seismic events in California. (2) Analyze InSAR data from ERS-1/2, ENVISAT, and ALOS to recover slow inter-seismic creep signals along the SAF system. The investigators are refining methods for stacking ERS and ENVISAT interferograms, as well developing new software for the analysis of L-band ALOS data. (3) Use the measurements of fault creep to improve our understanding of physical models for fault friction at shallow depth. In particular the analysis is revealing the relationship between creep rate, shallow stress accumulation rate, and major earthquake recurrence intervals.These proposed research activities are contributing to the objectives of NSF?s EarthScope Initiative by providing insight into fault mechanics and earthquake hazard. Funding will primarily be used to support graduate student research and training. This research has significant international collaboration with scientists at the Japanese and European Space Agencies. The researchers are also collaborating with the Scripps Institution of Oceanography (SIO) Visualization Center in cataloging and distributing images, animations, and 3-D visualizations. Educational activities include development of graduate and undergraduate courses at UCSD and presentations to local school groups on earthquake topics.

地面运动的非常精确的测量方法用于研究沿San Andreas断层（SAF）系统断层慢速蠕变的分布和幅度。测量和建模故障蠕变正在改善我们对地震危害和地震物理学的理解。 大部分蠕变信号都接近断层，因此，由于其完整的50米空间分辨率，因此最好通过一种称为干涉合成孔径雷达（INSAR）的空间技术观察到。 这项研究的新方面是使用最近启动的ALOS航天器（JAXA）的L波段Insar数据。 与先前可用的C波段干涉图相比，L波段干涉图在更长的时间间隔内保持连贯。 这些新数据在C-Band永久散射方法仅在测量缓慢的地壳变形方面部分成功的中部和北加州尤为重要。为期三年的调查包括以下任务：（1）参加北美西部Insar Insar联盟（WINSAR），以组装此调查所需的数据，并为加利福尼亚州的未来地震活动做准备。 （2）分析来自ERS-1/2，Envisat和ALOS的INS INAR数据，以恢复SAF系统沿SAF系统的慢速跨性蠕变信号。 研究人员正在完善堆叠ER和Envisat干涉图的方法，并开发了用于分析L波段ALOS数据的新软件。 （3）使用故障蠕变的测量值，以提高我们对浅深度故障摩擦的物理模型的理解。 特别地，分析揭示了蠕变率，浅应力积累率和主要地震复发间隔之间的关系。这些提议的研究活动通过提供对故障机械和地震危险的洞察力来促进NSF的Earthscope Initiative的目标。 资金将主要用于支持研究生的研究和培训。 这项研究与日本和欧洲太空机构的科学家进行了重要的国际合作。研究人员还与Scripps海洋学研究所（SIO）可视化中心合作，以编目和分发图像，动画和3D可视化。教育活动包括在UCSD开发研究生和本科课程以及向当地学校团体发表地震主题。