PhD Final Defense – Chunhui Zhao
- Event Type
- Seminar/Symposium
- Sponsor
- Department of Civil and Environmental Engineering
- Location
- CEEB 2012 (Conference Room)
- Virtual
- Join online
- Date
- Jan 8, 2026 8:00 am
- Views
- 1
Mechanics of Earthquake Ruptures in Complex Fault Zones
Advisor: Professor Ahmed Elbanna
Meeting ID: 817 2185 3379
Password: 141727Abstract
Earthquakes are among the most devastating natural hazards on Earth. While observations and laboratory experiments have advanced our understanding of seismic processes, near-source earthquake physics remains poorly constrained. Numerical modeling helps link observations to underlying physics, yet major challenges persist due to earthquake’s multiscale, geometrically complex, rheological nonlinear, and multi-physics nature. This dissertation presents MOOSE-FARMS, a MOOSE-based finite element framework for Fault and Rupture Mechanics Simulation, to address those challenges and interpret observations with physical mechanisms.
To demonstrate the critical role of geometric complexity, we analyze the 2023 Turkey–Syria earthquake using realistic fault traces and near-fault seismic records. Data-informed scientific inversion constrains near fault frictional properties and explains seemingly anomalous behaviors, highlighting how super-shear ruptures amplify local seismic hazards. For spatial multiscale and nonlinear rheology complexities, we implement a macro-mesoscale continuum damage-breakage (CDB) model within MOOSE-FARMS to characterize both distributed and localized off-fault damage patterns, in both single-fault and fault-network settings. Results show modulus degradation produces conjugate bands with enhanced high-frequency radiation. Studies with depth-dependent properties show stress drop controls damage generation, rate-dependent damage accumulation produce en echelon fractures, and depth-varying seismic properties produce flower-like structures near free surface, in agreement with field observations.
To investigate temporal complexity, we derive a finite deformation CDB model and examine factors controlling peak and residual strength. We then reproduce stick-slip events in lab-scale without prescription of rate-and-state friction and analyze slip spectrum within high-damage tabular zones, from fast rupture to tremor-like slow slip events. Finally, the multi-physics coupling with fluid is tackled through both coupled poroelastic–damage processes for pulse-power fracturing and borehole breakout tests. With fully coupled porosity, permeability, biot coefficient and damage, we validate the model against laboratory-scale damage geometries and stress–strain curves, paving the way towards future multi-physics earthquake rupture modeling with lab-constrained parameters.