SCEC Award Number 23202 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Investigating the relationship between 3D fault structure and slip rates in the Eastern California shear zone
Investigator(s)
Name Organization
John Naliboff New Mexico Institute of Mining and Technology Veronica Prush New Mexico Institute of Mining and Technology
Other Participants
SCEC Priorities 3b, 3d, 3e SCEC Groups Geology, CXM, SAFS
Report Due Date 03/15/2024 Date Report Submitted 03/15/2024
Project Abstract
 This project focused on examining the role of fault strength and structure on long-term slip rates within the Eastern California shear zone (ECSZ) portion of the PNA plate boundary system. To elucidate this relationship, we developed 3D boundary-driven simulations of the Northern ECSZ that integrate existing fault data from the SCEC community models. Our preliminary findings suggest fault width, strength, and variations in along-strike geometry all combine to influence long-term slip rates, and future work may be able to constrain these properties through comparisons to measured geologic slip rates.
Intellectual Merit This project and related future work will help constrain the geometry and properties of fault damage zones in both the brittle and ductile domains (P3.b), the geometry of active faults in the northern ECSZ at depth (SCEC Priority P3.d), and the extent of permanent, off-fault deformation, and its contribution to geologic and geodetic fault slip-rate estimates (P3.e). The underlying numerical approach to constraining these properties and processes involved developing new workflows for geologic and geophysical data integration, and extensive testing and modification of the physics-based forward simulations to accurately solve the system of equations with significant contrasts in material strength and adaptively refined mesh within the fault zones.

P3.b. Constrain the geometry of active faults across the full range of seismogenic depths, including structures that link and transfer deformation between faults. (CXM, Seismology, Geodesy, Geology, SAFS).
P3.d. Determine how damage zones, crack healing and cementation, fault zone mineralogy, and off-fault damage govern the degree of strain localization, the state and stability of slip (e.g., creeping vs. locked, seismic vs aseismic), interseismic strength recovery, and rupture propagation. (FARM, Geology, CS)
P3.e Constrain the extent of permanent, off-fault deformation, and its contribution to geologic and geodetic fault slip-rate estimates (Geology, SAFS, Geodesy, FARM, EFP
Broader Impacts The outcomes of this project will provide both the SCEC and broader earthquake science community new open-source workflows and tools for assessing the relationship between 3D fault network structure and both long-term slip rates and off-fault deformation. The projected training a primarily field-based graduate student in the fundamentals of computational modeling, whose also participated in the 2022 Pilot SCEC Scholars Program.
Exemplary Figure Figure 4