Fully Dynamic Rupture Modeling of Faults in Saturated porous media

Amr A. Ibrahim, Chunhui Zhao, & Ahmed E. Elbanna

Published September 8, 2024, SCEC Contribution #13979, 2024 SCEC Annual Meeting Poster #153

Dynamic rupture processes for faults embedded in saturated porous media have garnered significant research interest recently. Despite this, fully dynamic rupture models that incorporate both solid and fluid inertial effects remain limited. To this end, we present a mixed finite element formulation in our MOOSE-FARMS dynamic rupture simulator that addresses this gap by solving for displacements, pore pressures, and fluid fluxes to simulate dynamic ruptures in fully saturated porous media. Our approach employs the traction-at-split-node (TSN) method to accommodate displacement discontinuities and fluid fluxes on the fault surface, seamlessly integrating frictional boundary conditions within the FEM model. The frictional constitutive laws follow slip-weakening laws, with future work aiming to include rate-and-state laws. The fault plane is modeled as both impermeable and permeable to fluid, with potential extensions to leaky fault models and hydraulic fracture constitutive laws.

Our study includes 2D simulations of spontaneous rupture in saturated porous media, with plans to extend to 3D simulations in the future. We employ a fully dynamic finite element method that considers inertia effects from both solid and fluid phases. We explore the alteration of effective normal compressive stress due to rupture-induced pore pressure and investigate the dynamic effects of fluids, particularly under the context of supershear ruptures with varying porosities and permeabilities of damage zones. Additionally, we examine the impact of these factors on wave propagation properties. Our findings provide valuable insights into the complex interplay between fluid dynamics and fault mechanics, advancing the understanding of earthquake processes in in saturated porous environments.

Key Words
Poroelastodynamics; Fully Dynamic; Fluid Inertial Terms; Rupture Dynamics; Impermeable Fault; Permeable Fault

Citation
Ibrahim, A. A., Zhao, C., & Elbanna, A. E. (2024, 09). Fully Dynamic Rupture Modeling of Faults in Saturated porous media. Poster Presentation at 2024 SCEC Annual Meeting.

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