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

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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.