The Long-Term Dynamics and Evolution of Geometrically Complex Fault Systems

几何复杂断层系统的长期动力学和演化

• 批准号: 0409836
• 负责人: David Oglesby
• 金额: $ 16.23万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409836&HistoricalAwards=false
• 关键词: Long; Term; Dynamics; Evolution; Geometrically

Most earthquakes take place on geometrically complex fault systems rather than simple planar faults. Recent earthquakes on such fault systems have shown quite clearly the important effects of fault geometry on the dynamics of earthquake rupture, slip, and ground motion. This project is to study the dynamics of geometrically complex fault systems over multiple earthquake cycles using numerical simulations. Specific fault geometries to be addressed include faults with bends, faults with branches, and faults with offset segments. To accomplish this task, dynamic models for the earthquake rupture and slip process are being integrated with quasi-static models to simulate the processes of slow tectonic loading, nucleation, and post-seismic relaxation. An integrated algorithm to model these processes is being developed in this research. Using this technique, the researchers are modeling the complete earthquake cycle: initial stress distributions on faults before an earthquake rupture are a consequence of slow tectonic loading, stress relaxation, and residual stress from previous ruptures. Nucleation is also be spontaneously developed, and dynamic rupture patterns and ground motion are calculated. Thus, the long-term effects of fault geometry and characteristic behaviors of fault systems over multiple earthquake cycles are addressed in a self-consistent manner. The results will aid in the interpretation of recorded earthquakes on geometrically complex fault systems, such the Hector Mine and Chi-Chi events. The results will also aid in the prediction of future behavior of complex fault systems such as the San Andreas, as well as the ground motion during earthquakes on these faults.

大多数地震发生在几何复杂的断层系统上，而不是简单的平面断层。 这种断层系统上最近的地震清楚地表明了断层几何形状对地震破裂，滑动和地面运动动态的重要影响。该项目是使用数值模拟研究多个地震循环上几何复杂断层系统的动力学。要解决的特定故障几何形状包括带有弯曲的故障，带有分支的故障以及带有偏移段的故障。为了完成这项任务，将地震破裂和滑动过程的动态模型与准静态​​模型集成在一起，以模拟慢速构造负荷，成核和后观测后放松的过程。在这项研究中正在开发一种建模这些过程的集成算法。 使用此技术，研究人员正在对完全的地震周期进行建模：地震破裂之前的故障上的初始应力分布是较慢的构造负荷，应力松弛和先前破裂的残留应力的结果。 还会自发发展成核，并计算动态破裂模式和地面运动。因此，断层几何形状和断层系统对多个地震周期的特征行为的长期影响是以自洽的方式解决的。结果将有助于解释在几何复杂的断层系统（例如Hector矿山和CHI CHI事件）上记录的地震。结果还将有助于预测复杂断层系统（例如San Andreas）的未来行为，以及这些断层地震期间的地面运动。