Group A, Poster #185, Stress and Deformation Over Time (SDOT)

Regularized internal rate and state friction in the context of a damage-breakage rheology

Casper Pranger, Dave A. May, Ludovic Raess, Yehuda Ben-Zion, & Alice-Agnes Gabriel
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Poster Presentation

2022 SCEC Annual Meeting, Poster #185, SCEC Contribution #12010 VIEW PDF
A recently developed formulation of rate and state friction (Pranger et al., 2022) treats friction as an internal process in a granular medium, instead of its conventional treatment as a process on a surface between juxtaposed rocks. The spurious mesh-dependency that is typically associated with strain softening rheologies is avoided by including a diffusion process with an artificially boosted diffusion length scale. The overall character of the simulated seismic cycle is not meaningfully affected by the inclusion of this diffusion process, provided the associated length scale is well resolved by the spatial discretization. No other new parameters are introduced. The regularized, internal r...ate and state friction model produces patterns of pre-seismic strain localization and co-seismic and post-seismic strain delocalization that are not modeled by the interfacial rate and state friction law, and provide additional testable predictions.

The damage-breakage rheology (DBR) of Lyakhovsky and Ben Zion (2014a,b) is both significantly broader in scope and better grounded in the thermodynamic theory of irreversible processes than the phenomenological rate and state friction law. We aim to show how our extended rate and state rheology can be understood as the breakage component of the DBR rheology. This can facilitate adding the damage component of the DBR rheology to our existing model, in order to resolve the transition from intact rock to frictional instability through the accumulation of material damage.

Pranger et al. (2022), Rate and state friction as a spatially regularized transient viscous flow law. Journal of Geophysical Research: Solid Earth, 127, e2021JB023511.
Lyakhovsky and Ben-Zion (2014a), Damage–breakage rheology model and solid-granular transition near brittle instability. Journal of the Mechanics and Physics of Solids, 64, 184-197.
Lyakhovsky and Ben-Zion (2014b), A Continuum Damage–Breakage Faulting Model and Solid-Granular Transitions. Pure and Applied Geophysics, 171, 3099–3123