SCEC2022 Plenary Talk, Fault and Rupture Mechanics (FARM)
Modeling co-evolution of slip and fault zones in a Sequence of Earthquakes and Aseismic Slip (SEAS) model with off-fault plasticity
Oral Presentation
2022 SCEC Annual Meeting, SCEC Contribution #12495
ntly, reduces the computational cost and enable higher resolution. We use a rate-dependent pressure-sensitive non-associative Drucker-Prager plasticity model to approximate the inelastic response of the fault zone.
When considering a single fault, our results suggest that bulk plasticity plays an important role in the co-evolution of fault zones and seismicity with strong feedback on the local stress fields. Aseismic deformation and aseismic plastic strain accumulation evolve the stress field and bias plasticity accumulation during dynamic ruptures leading to damage patterns that deviate from the traditional off-fault fan-like distribution observed in single dynamic rupture simulations and emphasizes the significance of long-term deformation in interpreting observations. We tie our findings with field observations regarding the scaling of damage zone width with respect to distance from the fault and slip. Furthermore, we observe that weak fault zones, as parametrized by lower values of yield strength, may favor rupture segmentation and complex spatio-temporal seismicity, while stronger fault zones show reduced complexity and quasi periodic earthquake pattern. This underscores the critical role of the time-dependent partitioning of deformation between fault slip and bulk plasticity. Moreover, when incorporating increased geometrical complexity through a model of compressional fault step-over, as an example, we demonstrate that plastic strain accumulation in the overlapping region may enhance fault interaction resulting in additional seismic events. Our on-going work contributes to understanding the interaction between nearby faults with nonlinear off-fault bulk rheology and complement the development of next generation physics-based seismic hazard models.
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When considering a single fault, our results suggest that bulk plasticity plays an important role in the co-evolution of fault zones and seismicity with strong feedback on the local stress fields. Aseismic deformation and aseismic plastic strain accumulation evolve the stress field and bias plasticity accumulation during dynamic ruptures leading to damage patterns that deviate from the traditional off-fault fan-like distribution observed in single dynamic rupture simulations and emphasizes the significance of long-term deformation in interpreting observations. We tie our findings with field observations regarding the scaling of damage zone width with respect to distance from the fault and slip. Furthermore, we observe that weak fault zones, as parametrized by lower values of yield strength, may favor rupture segmentation and complex spatio-temporal seismicity, while stronger fault zones show reduced complexity and quasi periodic earthquake pattern. This underscores the critical role of the time-dependent partitioning of deformation between fault slip and bulk plasticity. Moreover, when incorporating increased geometrical complexity through a model of compressional fault step-over, as an example, we demonstrate that plastic strain accumulation in the overlapping region may enhance fault interaction resulting in additional seismic events. Our on-going work contributes to understanding the interaction between nearby faults with nonlinear off-fault bulk rheology and complement the development of next generation physics-based seismic hazard models.
SHOW MORE
Citation: Abdelmeguid, M., Mia, M., & Elbanna, A. E. (2022, 09). Modeling co-evolution of slip and fault zones in a Sequence of Earthquakes and Aseismic Slip (SEAS) model with off-fault plasticity. Oral Presentation at 2022 SCEC Annual Meeting.
Relevant SCEC Themes:
SCEC Annual Meeting Abstract Themes:
Stress and Deformation Over Time
Beyond Elasticity
Modeling Earthquake Source Processes
