Automatic Time Step Control to Resolve Hydromechanically Driven Fault Reactivation, Spontaneous Nucleation, and Seismic Arrest

• Published in: Water resources research 2023-11, Vol.59 (11), p.n/a
• Main Authors: Han, Zheng, Ren, Guotong, Younis, Rami M.
• Format: Article
• Language: English
• Subjects: Control methods; critical nucleation length; Deformation; Engineering; First principles; Heterogeneity; induced seismicity; Nucleation; poromechanical simulation; Rupture; Seismicity; timestep control
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/2023WR035626

A physical understanding of the progression from flow‐driven (quasi‐static) poromechanical deformation to dynamic fault rupture is critical to the resilient operations of several engineering systems. These processes are bridged by a progression from fault reactivation to the spontaneous nucleation of unstable sliding. Toward addressing this challenge, novel automatic time step size control methods are developed to enable accurate and efficient simulation of these dynamics and transitions from the first principles. The controllers combine local models for discretization error and Coulomb failure conditions to automatically adjust the time step size across several orders of magnitude. The methods do not require additional empirical or theoretical input and can resolve the pre‐rupture, interseismic, and seismic periods to the allowed accuracy. The computational results reveal that the proposed methods automatically capture the onset of reactivation and nucleation for homogeneous and heterogeneous fields. Hydrodynamic and structural heterogeneity lead to disparate critical nucleation sizes compared to those predicted by theory. The results highlight its potential in predicting induced seismicity in realistic subsurface engineering systems and at practical scales. Key Points Automatic time step controller to resolve flow, fault reactivation, and coseismic rupture under geologic complexity from first principles Simultaneous local error control and monitoring of rupture progression to adapt the simulation time scale across seven orders of magnitude Simulations (multiphase flow and inertial mechanics) of complex scenarios show alternative approaches can be significantly inaccurate