SCEC Award Number 16018 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Dynamic and Kinematic Modeling of Branch Faulting in Strike-Slip Faults
Investigator(s)
Name Organization
Jeff Bayless AECOM Paul Somerville AECOM Percy Galvez AECOM
Other Participants
SCEC Priorities 4a, 4e, 6b SCEC Groups GMSV, GMP, FARM
Report Due Date 03/15/2017 Date Report Submitted 03/15/2017
Project Abstract
 We use dynamic rupture modeling to investigate the conditions under which branching strike-slip faulting can occur, and use that information to guide kinematic broadband ground motion simulations of branching strike-slip faulting. We perform dynamic earthquake rupture modeling with an unstructured 3-D spectral element method to model the Hosgri – Shoreline fault system and explore the conditions under which branch faulting occurs. We explore how rupture initiates on the branch fault, and use these results to kinematically model the location and timing of the branch rupture. We also evaluate the dynamic source parameters such as rise time, slip duration and final slip of the individual fault segments, to generate guidelines for multi-segment branching kinematic simulations.
Intellectual Merit Ground motion prediction equations are based on a single fault plane representation of the earthquake source, and therefore do not provide reliable estimates of ground motions from complex fault systems such as branching strike-slip faults. Kinematic ground motion simulation can be used to estimate the ground motions from such complex faults, but there are many uncertainties in the details of how the different fault segments interact which can only be addressed using dynamic rupture modeling. For example, branched faulting can only occur under a limited range of conditions (Kame et al., 2003). We need to understand how rupture initiates on the branch fault, so that we can kinematically model the location and timing of the branch rupture. In the modeling of individual fault segments, we need to know which source parameters such as rise time, slip duration and final slip should be determined from the seismic moment of the branching segment rather than those of the overall event.
Broader Impacts This project has supported the already strong collaboration of the group of scientists who work on and for the SCEC broadband platform, by contributing to the research goals and interacting on a regular basis with scientists (and engineers.) Possible benefits of the activity to society involve the improvement of earthquake simulations, which will eventually be used in seismic design, particularly for near fault ground motions.
Exemplary Figure Figure 4. The snapshot sequence of the branching rupture for the Hosgri-Shoreline using dynamic rupture modeling.