SCEC Award Number 15017 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Collaborative proposal from UCSD and Caltech: SCEC Community Data Products of Relocated Seismicity, Improved Focal Mechanisms, and Waveform Spectra for Resolving Fine-Scale Fault Structures and State of Stress in Southern California
Name Organization
Egill Hauksson California Institute of Technology Peter Shearer University of California, San Diego
Other Participants Thomas Goebel or other TBN Caltech postdoc (just for 1 month); TBN (UCSD grad student)
SCEC Priorities 2a, 2d, 2f SCEC Groups Seismology, EFP, USR
Report Due Date 03/15/2016 Date Report Submitted 03/06/2016
Project Abstract
Our research represents the continuation of an ongoing and very successful collaboration between Caltech and UCSD to perform automatic processing of the SCSN waveform archive. Our SCEC work so far has focused on improving earthquake locations and focal mechanisms using waveform cross-correlation and S/P amplitude ratios, and on computing spectra for use in studies of earthquake source properties and attenuation. These results are described in many papers published in previous years (Hauksson and Shearer, 2005, 2006; Shearer et al., 2005, 2006; Lin et al., 2007a,b, 2008; Allmann et al., 2008; Lin and Shearer, 2009; Hauksson, 2010, 2011; Hauksson et al., 2012; Chen and Shearer, 2011, 2012; Yang et al., 2011, 2012; Hauksson, 2014).

The latest version of our relocated catalog (the HYS catalog) contains high-precision locations of over 582,000 events from 1981 through 2015. Our previous catalogs, such as the LHS catalog by Lin et al. (2007b) have been widely used by other researchers, leading to new results on a number of topics, including earthquake triggering, swarms, locking depth, and earthquake scaling, which would not have been possible with standard catalogs.
Intellectual Merit This project relates to many key SCEC objectives and will improve our understanding of earthquake activity across southern California. In particular, our high-resolution earthquake locations provide better delineation of fault structures and make possible more advanced seismicity studies by us and other SCEC researchers. Our focal mechanism catalogs and stress drop analyses provide fundamental insights into the earthquake rupture process and the relationships between micro-earthquake activity, the crustal strain field, and major faults.
Broader Impacts Outreach activities consist of providing the relocated catalog to SCEC scientists and others doing research on seismicity in southern California. The relocated catalog is available at the Southern California Earthquake Data Center (SCEDC). We have also presented results at SCEC workshops.
Exemplary Figure Figure 3 in report