SCEC Award Number 21112 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Collaborative Proposal: A Comparative Investigation of Off-Fault Inelastic Processes: From Plasticity to Multiscale Damage
Name Organization
Ahmed Elbanna University of Illinois at Urbana-Champaign Alice-Agnes Gabriel University of California, San Diego Yehuda Ben-Zion University of Southern California
Other Participants
SCEC Priorities 1d, 2d, 3d SCEC Groups FARM, CS, Seismology
Report Due Date 03/15/2022 Date Report Submitted 05/03/2022
Project Abstract
We propose to critically evaluate the appropriateness of different off-fault inelasticity models and the extent to which they are consistent with observations. We plan to do this by running a series of controlled 2D dynamic rupture simulations, along with a few carefully selected 3D simulations, and compare different rupture and ground motion characteristics in the following three scenarios: (1) Dynamic rupture with off-fault Drucker-Prager plasticity model, (2) Dynamic rupture with off- fault continuum damage model, and (3) Dynamic rupture with generation of discrete secondary cracks. If successful, this research will: (1) identify the limitations and capabilities of the different models for off- fault inelastic deformation in the upper crust, (2) evaluate the unique signatures of different inelastic deformation rheologies (plasticity, distributed damage, localized fractures) in near and far-field observations, and (3) design benchmark problems for verification of dynamic rupture simulations with off- fault continuum and discrete damage.
Intellectual Merit Development of computational tools for modeling different facets of fault zone inelasticity including damage, breakage, plasticity, and the spontaneous generation of secondary cracks will enable transformative opportunities in studies of earthquake physics including exploring the novel frontier of co-evolution of faults, fault zones, and earthquakes as well as quantitative constraints on different seismological and geological observables such as ground motion, energy budget, surface deformation, and fault zone structure.
Broader Impacts Training of two PhD students at UIUC: Md Shumon Mia (MechSe) and Chunhui Zhao (CEE) who are working on developing computational tools for modeling sequence of earthquakes and aseismic slip with off-fault inelasticity including plasticity, damage, and nucleation and propagation of off-fault cracks. Training of a PostDoc (C. Pranger) and PhD student (J.N. Hayek, URM student) in Gabriel’s group.
Exemplary Figure Figure 1: Preliminary results from simulations obtained for the newly developed rate-and-state friction consistent phase field formulation. (a) Propagation of a horizontal fault in an anti-plane setting in an otherwise intact domain. The fault grew from a small pre-existing patch and the co-evolution of a central extremely localized fault surface (dark red) and a less damaged off-fault region (lighter color) is observed. (b) Quasi-dynamic fault growth in a heterogeneous fault zone with variable fracture energy showing evolution of multiple fault cores analogous to the complex fault zone structures observed in some strike slip fault structures. (Fei et al. in preparation)