Modeling dynamic ruptures with high resolution fault zone physics

Earthquake, Dynamic Rupture Modeling

Ma, Xiao

关键词: Earthquake, Dynamic Rupture Modeling;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/106148/MA-DISSERTATION-2019.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Earthquakes are among the costliest natural hazards on earth. The dynamical instabilities responsible for the onset and propagation of these events are linked to fundamental physics, friction, fracture, heating, and compaction of fluid filled granular materials and rocks in the subsurface subjected to extreme geophysical conditions. Due to the wide range of spatial and temporal scales characteristic of the earthquake source processes, computational modeling of these processes continue to be a major challenge.In this research, we address this challenge by developing new models that shed novel insights into the different faces of complexity of the earthquake source. We first introduce the investigation of a complex fault zone structure and its effect on earthquake dynamic rupture mode transition. We show, for the first time, that the existence of soft inclusions off the fault plane may promote supershear transition under low prestress conditions. Secondly, we look further into the material behavior within the fault zone and develop a non-equilibrium statistical thermodynamics-based viscoplastic framework for modeling granular systems within the Shear Transformation Zone theory. Thirdly, we present a new hybrid computational algorithm for modeling earthquake ruptures in complex fault zone structures. This method has the potential capability to bridge the spatial and temporal scales in earthquake models by leveraging advantages of both domain based and boundary based numerical schemes. Finally, we demonstrate the powerful capability of the hybrid approach by applying the method to solve a computationally challenging problem in earthquake dynamic rupture modeling by explicitly representing small scale secondary fault branches. We then discuss the potential future research direction along the lines of previous studies such as applying the developed numerical frameworks for solving complicated fault zone problems that couldn’t be solved by traditional numerical schemes; extending the hybrid scheme to simulate long term earthquake cycles incorporating geometric complexity and material nonlinearity. This research work will expand our understanding of earthquake rupture and will help us gain new insights into the complexity of earthquake mechanisms.