SCEC Award Number 12160 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title FOCAL MECHANISM ANALYSIS OF THE 2010 EL MAYOR-­‐CUCAPAH AFTERSHOCK SEQUENCE IN THE YUHA DESERT REGION
Investigator(s)
Name Organization
Gareth Funning University of California, Riverside Elizabeth Cochran United States Geological Survey
Other Participants Kroll, Kayla
SCEC Priorities 2a, 2d, 4c SCEC Groups Seismology
Report Due Date 03/15/2013 Date Report Submitted N/A
Project Abstract
 We present the results of Coulomb stress change modeling of the Yuha Desert in response to both the Mw7.2 4 April 2010 El Mayor-Cucapah and M 5.8 14 June 2010 Ocotillo, California earthquakes. We find that regions of Coulomb stress decrease coincide with decreased seismicity rates following the Ocotillo aftershock, effectively 'shutting off' the aftershock seismicity associated with the main shock in those areas.
Intellectual Merit The project explores the complex interactions between aftershocks following the largest event in the region in the past decade. It enhances both our understanding of the phenomenology of the event and its aftershocks, and the mechanisms of aftershock triggering and suppression.
Broader Impacts The project has broadened the participation an underrepresented group by training graduate student Kayla Kroll, who is a first generation college student and who did the majority of the work. It will serve as a portion of her doctoral dissertation.
Exemplary Figure Figure 5: Seismicity rate change calculated for 67 days following the Ocotillo mainshock compared to the 67 day period between the EMC and Ocotillo events. Red areas show an increase in seismicity rate, while blue shows seismicity rate decrease. Gray areas mark regions of insufficient data, where the calculations are not performed. The key feature of this plot is the blue area of seismicity rate decrease that coincides with the zone of Coulomb stress decrease from the Ocotillo aftershock, implying a shut-off in seismicity in those areas.