Faulting Process from Top to Bottom Along the San Andreas Fault in the San Juan Bautista Region

圣胡安包蒂斯塔地区沿圣安德烈亚斯断层自上而下的断层过程

• 批准号: 0951430
• 负责人: Roland Burgmann
• 金额: $ 38.18万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0951430&HistoricalAwards=false
• 关键词: Faulting; Process; Top; Bottom; Along

Understanding of the spatially and temporally varying deformation field around fault zones is critically important for understanding active tectonics, fault interaction and the occurrence of large earthquakes. This project is focused on the San Juan Bautista area of California, where the complexity of the fault structure and a variety of time-varying slow-slip (aseismic) phenomena make a perfect natural laboratory to study active faulting processes from the top of the Earth's surface to great depth. The site is also attractive because of the availability of a rich historic data set and the recent deployment of EarthScope instrumentation, including continuous GPS stations, strainmeters and seismometers.The project team is analyzing geodetic and seismic data in this region and integrating them to interpret the underlying architecture and mechanics of the faulting process. Creepmeter, strainmeter, GPS, and InSAR data constrain models of the four-dimensional distribution of fault slip in the upper crust. The geodetic data are complemented by information on aseismic slip deep below the surface inferred from repeating earthquakes. Furthermore, episodes of non-volcanic tremor hint at deformation transients at sub-seismogenic depths. Because fault slip is tied to the mechanical properties of the fault zone rocks and adjoining crustal blocks, the team is also evaluating changes in crustal properties through time using receiver-function analysis.These diverse data sets provide valuable information on the interactions between earthquakes and aseismic slip that occurs in various depth ranges in the fault zone. Results from this work provide insight into the role of aseismic fault slip transients in earthquake occurrence and clustering. Improved understanding of aseismic slip transients, their relation to regional strain anomalies, and improved models of the earthquake cycle may help to improve earthquake forecasts and intermediate to longer-term predictions.

了解断裂带周围时空变化的形变场对于理解活动构造、断层相互作用和大地震的发生至关重要。 该项目的重点是加州的圣胡安鲍蒂斯塔地区，那里复杂的断层结构和各种随时间变化的慢滑（aseprock）现象，使一个完美的天然实验室，研究活动断层过程从地球表面的顶部到很大的深度。 该场址的另一个吸引人之处是，它拥有丰富的历史数据集，最近还部署了EarthScope仪器，包括连续的全球定位系统站、应变仪和地震仪，项目小组正在分析该地区的大地测量和地震数据，并将其综合起来，以解释断层作用过程的基本结构和机制。 蠕变仪、应变仪、GPS和干涉合成孔径雷达数据限制了上地壳断层滑动四维分布的模型。大地测量数据得到了从重复地震中推断出的地表深处的地震滑动信息的补充。 此外，事件的非火山震颤暗示在变形瞬变在次孕震深度。由于断层滑动与断层带岩石和邻近地壳块体的力学性质有关，因此研究小组还使用接收函数分析来评估地壳性质随时间的变化。这些不同的数据集提供了有关地震和断层带不同深度范围内发生的地震滑动之间相互作用的宝贵信息。从这项工作的结果提供了洞察地震发生和集群的作用，地震断层滑动瞬变。提高对地震滑动瞬变及其与区域应变异常的关系的认识，改进地震周期模型，可能有助于改进地震预报和中长期预测。