SCEC Award Number 20091 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Simulating fully dynamic earthquake cycles on faults with heterogeneous stresses and fault damage zones
Name Organization
Yihe Huang University of Michigan
Other Participants Graduate student Prithvi Thakur will participate in the proposed project.
SCEC Priorities 1d, 3d, 3c SCEC Groups FARM, Seismology, CS
Report Due Date 03/15/2021 Date Report Submitted 03/15/2022
Project Abstract
The project aims to investigate and quantify how stress heterogeneities evolve on faults surrounded by fault damage zones through 2-D fully dynamic earthquake simulations. We will address how the evolution and spatial scale of fault stress heterogeneity correlate to the dimension and properties of fault damage zones and whether earthquake locations and size vary with time due to the evolving fault stress heterogeneity. Understanding these questions will be of fundamental importance for unveiling the contributions of stress and material heterogeneity to seismic and aseismic slip. Our results demonstrate that fault damage zones can produce stress heterogeneities even with uniform initial stress conditions, and these heterogeneities have a competing effect with the prescribed self-similar stress heterogeneities as fault slip accumulates. The prescription of initial stress heterogeneities also facilitates the intermediate magnitude sub-surface earthquakes to grow into large surface-reaching events. Our fully dynamic earthquake cycle simulations with fault damage zones show that such stress heterogeneities persist throughout the earthquake cycles and may even increase with the cumulative fault slip.
Intellectual Merit The project directly addresses the priorities of SCEC5 by quantifying the influence of stress heterogeneity on faults and understanding how the properties of fault damage zones affect the seismic and aseismic slip histories on active faults. The project also tackles two basic questions in the SCEC5 Science Plan: (1) How faults are loaded on different temporal and spatial scales, and (2) How the evolving structure, composition and physical properties of fault zones and surrounding rock affect shear resistance to seismic and aseismic slip. The project incorporates the presence of stress heterogeneities and fault damage zones in fully dynamic earthquake cycle simulations that reproduce both earthquake rupture and interseismic slip.
Broader Impacts The project supports the training of a graduate student. It also allows us to participate in the benchmark of fully dynamic earthquake cycle simulations in the SCEC Sequences of Earthquakes and Aseismic Slip Project and further improve the computational efficiency of our code.
Exemplary Figure Figure 3 from the report
Figure caption: Earthquake cycles in the heterogenous stress simulation. (a) Cumulative slip contours with orange lines plotted every 0.1 sec and blue lines plotted every 2 years. (b) Peak slip rate on the fault shown as a function of time. (c) Depth distribution of earthquakes shown as a histogram with fixed bins. (d) The magnitude-frequency distribution of simulated earthquake sequences.
My student Prithvi Thakur generated the figure.