SCEC Award Number 18096
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Effects of fault zone damage on rupture patterns throughout multiple earthquake cycles
Name Organization
Jean-Paul Ampuero California Institute of Technology
Other Participants Benjamin Idini, Graduate Student
SCEC Priorities 3d, 1d, 2e SCEC Groups FARM, Seismology, SDOT
Report Due Date 03/15/2019 Date Report Submitted No report submitted
Project Abstract
The overarching goal of this project is to understand the interactions between dynamic rupture processes and the structural evolution of damaged fault zones over long time scales. This year we have shown that, in computational and theoretical earthquake models, pre-existing damaged fault zones affect earthquake rupture persistently over multiple earthquake cycles. They lead to pulse-like ruptures and multiple back-propagating fronts reminiscent of Rapid Tremor Reversals. These complex rupture patterns can be new targets for future observational and laboratory studies.
Intellectual Merit This project is a computational-theoretical building block towards the challenging goal of understanding how dynamic rupture processes interact with the structural evolution of damaged fault zones over time scales of multiple earthquake cycles.
The proposed work addresses directly SCEC5 priority 3d to determine how damage zones govern rupture propagation. It also addresses priority 1d to model the influence of stress heterogeneity on faults at different spatial scales on rupture initiation, propagation, and arrest. The expected results are building blocks towards priority 2e to describe how fault complexity and inelastic deformation interact to determine the probability of rupture propagation through structural complexities.
Broader Impacts The project contributed to the doctoral thesis of an Hispanic graduate student, opportunities for him to showcase his results in AGU and SCEC conferences, and to participate in software verification and earthquake cycle modeling SCEC workshops. This work was one of his first-year graduate research projects, which he presented as part of his doctoral qualification examination in September 2018.
Exemplary Figure Figure 3. Ruptures in (left) a homogeneous medium and (middle) a LVFZ with D = 0.9 and h = Lnuc/4. The former is crack-like, while the latter is pulse-like and features multiple back-propagating fronts. (right) The heterogeneous stress before (black) and after (red) the rupture in LVFZ. Residual stress peaks correlate with the nucleation points of back-propagating fronts.
Idini and Ampuero.