SCEC Award Number 16050 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title SCEC Community Data Products of Relocated Seismicity and Improved Focal Mechanisms, for Resolving Fine-Scale Fault Structures and State of Stress in Southern California
Investigator(s)
Name Organization
Egill Hauksson California Institute of Technology
Other Participants Dr. Qiong Zhang, Postdoc
SCEC Priorities 2a, 2d, 2f SCEC Groups USR, EFP, Seismology
Report Due Date 03/15/2017 Date Report Submitted 03/14/2017
Project Abstract
The latest version of our waveform-relocated catalog (the HYS catalog) contains high-precision locations of over 597,000 earthquakes from 1981 through 2016.
In 2016 we focused on analyzing how the earthquakes focal depths depend on the velocity model used. Earthquake focal depths are difficult to determine because they are strongly dependent on the availability of P and S travel time data and the velocity model. We investigate how refined velocity models could possibly improve depth determination for the refined SCN catalog. Using a velocity model obtained from the waveform tomography as starting model (Lee et al., 2014), we invert for a new model that fits the P and S travel times best. We find out that focal depths relocated with the new model or with the waveform tomography model are shallower than those relocated with a previous travel time tomography model. In addition, the relative locations cluster differently, forming fewer but larger clusters.