SCEC Award Number 12099 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Dynamic Ruptures with Off-Fault Dissipation Processes: Constraints on Energy Partition, Size-Dependent Levels of Prestress
Investigator(s)
Name Organization
Ralph Archuleta University of California, Santa Barbara
Other Participants Ahmed Elbanna (Post-doc, UCSB)
SCEC Priorities 4b, 3c, 3e SCEC Groups FARM, CS, SDOT
Report Due Date 03/15/2013 Date Report Submitted N/A
Project Abstract
 In this reporting period we continued our work investigating the dynamics of rupture propagation on frictional interfaces with different bulk constitutive response. In particular we examined the implications of off-fault plasticity on rupture parameters such as fracture energy, peak slip rates, rupture propagation speed and rupture mode. We are also currently looking into implications of off-fault plasticity on stress evolution in earthquake cycle simulations. Our work addresses several SCEC priority science objectives in Fault and Rupture Mechanics (3c,3d,3e and 4b) by developing physically-based self-consistent dynamic rupture models that investigate the relative contribution of on and off-fault damage and plasticity as well as assessing its impact on maximum slip rates, rupture speed and the absolute levels of the local and average prestress
Intellectual Merit We have also found a different mode of rupture propagation that we have not observed previously in elastoplastic scenarios with uniform normal stresses as shown in Figure 4. After off-fault plasticity is triggered, and as the rupture front is propagating into areas with decreasing normal and shear stresses, the healing tip starts to slow down. A stress concentration starts to build up at the healing end which eventually becomes large enough to trigger a train of pulses that propagates in the opposite direction of the initial rupture. These features persist with increasing the spatio-temporal resolution. Re-fracturing at the healing end was reported previously in the context of self-similar pulses in elastic media [Nielsen and Madariaga, 2003; Gabriel et al., 2012].
Broader Impacts This supports an early career postdoctoral researcher, now an assistant professor at the University of Illinois, Champaign-Urbana.
Exemplary Figure Figure 4