Single-Event and Long-Term Dynamics of Nonplanar Fault Systems

布列塔尼·A·埃里克森博士获得了美国国家科学基金会地球科学博士后奖学金，在斯坦福大学开展一项研究和教育计划。将在地球物理和数学领域之间进行跨学科研究，以了解地震模拟中出现的未知现象，这些现象具有以前没有研究过的某些物理特征。这项工作将研究断层系统的动力学模型，以探索小尺度非平面特征如何影响单粒子破裂行为，以及断层网络中的长期相互作用。对于故障网络的单事件和长期建模，从来没有人研究过对故障地形如此复杂详细的描述。有观点认为，具有复杂几何形状的断层，包括弯曲和断层分支，会影响成核、传播和止裂等破裂性质。了解破裂如何以及为什么会破坏多个断层段，或跳转到附近的断层线，在地震危险性评估中起着重要的作用。该项目的目标是：(1)了解小尺度非平面特征和断层外塑性等物理特征如何影响破裂动力学，(2)探索破裂在几何复杂的断层网络中传播的路径，(3)进一步开发能够解决准静态问题并模拟长期动力学的计算机代码，(4)计算与小尺度粗糙度断层的跳跃和分支相关的统计数据。将开发非平面断层上单次事件和长期地震动力学的高性能数值编码，并在计算机集群上模拟该代码。这项工作的结果将极大地影响对真实断层网络中的地震成核、破裂行为、跳跃和分支的地震危险性的估计。它将确定哪些地区更容易受到更大地震破坏的影响。此外，地震破裂从一个断层跳到另一个断层的可能性意味着，如果只涉及一个断层，破裂过程的持续时间可能比预期的要长，从而增加了对建筑物和建筑物的破坏性地面运动量。该项目将适当量化与地震破裂有关的统计数据，并适当评估与地震活动有关的风险和损失。教育计划包括在参与的地球物理学家的课程和讲习班中分享数学知识，以便对研究人员进行计算科学方面的教育。

Dr. Brittany A. Erickson has been granted the NSF Earth Sciences postdoctoral fellowship to carry out a research and education plan at Stanford University. Interdisciplinary research between the fields of geophysics and mathematics will be conducted in order to understand unknown phenomena emerging from earthquake simulations with certain physical features that have not been previously studied. This work will study dynamic models of fault systems in order to explore how small-scale nonplanar features influence single event rupture behavior, as well as long term interactions in fault networks. Single-event and long-term modeling of fault networks has never been studied with such an intricately detailed description of fault topography that will be considered. It has been suggested that faults with complex geometries, including bends and fault branching, affect such rupture properties as nucleation, propagation and arrest. Understanding how and why ruptures break multiple fault segments, or jump to nearby fault lines plays an important role in seismic hazard assessment. The goals of this project are: (1) to understand how the incorporation of such physical features as small-scale non-planar features and off-fault plasticity affect rupture dynamics, (2) to explore the path through which ruptures propagate in a geometrically complicated fault network, (3) to further develop computer codes to be able to solve the quasi-static problem and simulate long term dynamics, (4) to compute statistics associated with jumping and branching of faults with small scale roughness. High performance numerical coding of single event and long term earthquake dynamics on nonplanar faults will be developed and the code will be simulated on clusters of computers. The results from this work will greatly affect seismic hazard estimates of earthquake nucleation, rupture behavior, jumping and branching in real fault networks. It will determine the regions more susceptible to greater earthquake damage. Furthermore, the possibility for an earthquake rupture to jump from one fault to another implies that the duration of the rupture process can be longer than expected if only one fault is involved and consequently increase the amount of damaging ground motion to structures and buildings. This project will properly quantify the statistics involved with earthquake rupture and allow for a proper assessment of the risk and damages associated with earthquake activities. The education plan includes sharing of mathematical knowledge in courses and workshops for the geophysicists involved in order to educate researchers in computational science.