SCEC Award Number 13003 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Continuing studies of seismicity rate changes in southern California following the 2010 M7.2 El Mayor-Cucapah Earthquake and migration pattern of the 2012 Brawley swarm
Investigator(s)
Name Organization
Zhigang Peng Georgia Institute of Technology
Other Participants Meng, Xiaofeng, and one SCEC/SURE intern
SCEC Priorities 2, 4, 5 SCEC Groups Seismology, FARM, CS
Report Due Date 03/15/2014 Date Report Submitted N/A
Project Abstract
 We continued the effort of a systematic detection of missing earthquakes in Southern California following the El Mayor-Cucapah mainshock [Meng et al., 2012, 2013b, 2013c; Meng and Peng, 2014]. By performing the detection on a supercomputing GPU cluster ‘Keeneland’, we obtained a near-complete earthquake catalog in the San Jacinto Fault Zone (SJFZ) and the Salton Sea Geothermal Field (SSGF) [Meng and Peng, 2014]. We also applied the same technique to investigate seismicity rate changes following the mainshock in whole southern California region. Both studies show that there was a clear seismicity rate increase immediately following the mainshock, while the longer-term seismicity rate changes pattern were consistent with the static Coulomb Failure Stress (sCFS) changes pattern. The observations suggest that dynamic and static triggering may be dominant in short- and longer-term time period, respectively.
Intellectual Merit Our research project directly addresses the following Fundamental Problems in Earthquake Physics as outlined in the SCEC4 RFP: (1) 2a “Improvement of earthquake catalogs …”; and 2b “Improved description of triggered earthquakes”. In addition, it fits well with the one of the Key Problems in Computational Sciences on “Data-intensive computing”.
Broader Impacts This project provided a partial support for the GT graduate student Xiaofeng Meng, who is expected to finish his Ph.D. in May 2015. Xiaofeng has become an expert in this topic, as evident by several manuscripts published over the last a few years. The results from this project will become a major component of his Ph.D. thesis. This project also provided a partial support for a summer intern Gavin Rinaldo (GT undergrad student in summer 2013). Gavin worked together with Xiaofeng on detecting missing events during the 2013 Mw4.7 Anza earthquake sequence [Rinaldo et al., 2013].
Exemplary Figure Figure 1. (a) Static Coulomb stress changes in southern California following the 2010 Mw7.2 El Mayor-Cucapah earthquake. (b) The seismicity rate changes in the SSGF showing a short-time increase and long-term decrease following the main shock. The vertical bars denote the daily number of detected events versus times around the main shock. The blue line denotes the cumulative number of detected events. The red dashed line denotes the average pre-shock rate. The green shadow areas denote the data gaps. (c) and (d) The seismicity rate changes in Segment b and c in the SJFZ showing both short-term and long-term increase following the main shock. (Modified from Meng and Peng, 2014).