SCEC Award Number 12189 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Implementation of background seismicity in the physics-based earthquake simulator RSQSim
Investigator(s)
Name Organization
Keith Richards-Dinger University of California, Riverside
Other Participants
SCEC Priorities 2e, 4e, 2b SCEC Groups Simulators, WGCEP, EFP
Report Due Date 03/15/2013 Date Report Submitted 11/14/2017
Project Abstract
 Typically synthetic seismic catalogs from earthquake simulators only include those earthquakes that occur on the explicitly modeled faults in the fault system used by the simulator. However, a large fraction of natural seismicity (including most aftershocks of large events) occurs on pervasive unmodeled small-scale faults. The work under this proposal was aimed at allowing RSQSim to model these events as well in order to
1) facilitate comparison with real seismicity catalogs;
2) allow more complete exploration of the effects of geometrical complexity, fault
constitutive properties, and other model input parameters on the spatial-temporal
clustering of earthquakes;
3) provide direct simulator-based estimates of seismic hazard from these “off-fault” events (which correspond closely to UCERF2’s background seismicity).
Intellectual Merit This project concentrates on the SCEC Interdisciplinary Focus Area, Earthquake Forecasting and Predictability (EFP), and it specifically addresses the following priority topics.
• Support the development of statistical or physics-based real-time earthquake forecasts.
• Utilize and/or evaluate the significance of earthquake simulator results.
• Focus on understanding patterns of seismicity in time and space, as long as they are aimed toward understanding the physical basis of earthquake predictability.
Broader Impacts Graduate student Kayla Kroll and researcher Heming Xu gained valuable experience in running RSQSim, analyzing the results, and (in the case of Heming Xu) developing the background seismicity code.
Exemplary Figure Fig. 3: Left) Observed aftershocks following the magnitude Mw=7.2, 04/04/2010 El Mayor- Cucapah earthquake. Aftershocks between El Mayor-Cucapah and the 06/14/2010 M5.9 Ocotillo aftershock are in blue and earthquakes following Ocotillo are shown in red. Simulated on-fault and background aftershocks of an M7.2 RSQSim event on the Laguna Salada Fault. Aftershocks between the Laguna Salada event and an (explicit RSQSim) M5.9 aftershock in blue and those after the M5.9 in red.
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