3D dynamic rupture modeling with depth-dependent stress using nonlocal continuum damage breakage rheology

Chunhui Zhao, Ahmed E. Elbanna, & Yehuda Ben-Zion

Submitted September 7, 2025, SCEC Contribution #14908, 2025 SCEC Annual Meeting Poster #TBD

Understanding the interplay of earthquakes and off-fault damage is crucial for understanding earthquake processes and linking surface observations to deformations at depth addressing. While numerical earthquake models are indispensable for bridging observational gaps, they still face significant challenges in capturing the fundamental mechanics of faulting and rupture: for example, the organization of fracture networks, evolving seismicity, and stress/ strain leading to large failure events.

To this end, we leverage a three-dimensional nonlocal continuum damage–breakage model (CDBM) with depth-dependent stress conditions to examine two scenarios: (1) a fully hydrostatic pore-pressure profile, producing stress that increases linearly with depth to the fault’s bottom boundary; and (2) a profile that is hydrostatic near the surface but transitions at a threshold depth to lithostatic due to over pressurization, yielding constant effective normal stress at greater depths. We then quantify differences in rupture dynamics, off-fault damage, energy partitioning, and high-frequency seismic radiation for varying strain-rate dependent damage evolution.

The simulations reproduce distributed damage, localized off-fault branching and a funnel-shaped damage zone, reveal a clear depth dependence. Under a uniformly hydrostatic pore-pressure profile, damage concentrates at greater depths; when rupture nucleates within a lithostatic zone, damage instead localizes in the shallow subsurface, within the near-surface hydrostatic region. Records from selected on- and off-fault receivers show systematic differences in particle velocity and high-frequency radiation that diagnose the depth of damage generation. This 3D framework links surface observations and seismicity to subsurface physics, enabling studies of fracture-network genesis, rupture evolution, and the effects of depth-dependent normal stress on energy dissipation and ground motion.

This numerical approach is implemented in our MOOSE–FARMS rupture simulator: CDBM governs the entire computational domain, with preexisting faults represented as sharp interfaces follows a linear slip-weakening law, and mesh-sensitive strain localization is eliminated through a nonlocal strain-invariant ratio that regularizes damage evolution. This full simulator is publicly accessible via Quakeworx, an NSF-funded science gateway designed to democratize access to advanced earthquake simulations and associated datasets.

Citation
Zhao, C., Elbanna, A. E., & Ben-Zion, Y. (2025, 09). 3D dynamic rupture modeling with depth-dependent stress using nonlocal continuum damage breakage rheology. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)