SCEC Award Number 14180 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Detecting Low-Frequency Earthquakes within Deep Tremor in California
Investigator(s)
Name Organization
Zhigang Peng Georgia Institute of Technology Hongfeng Yang Georgia Institute of Technology
Other Participants
SCEC Priorities 1c, 5a, 5c SCEC Groups Seismology, FARM, EFP
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
 We continued the effort of a systematic search of tremors in California. The lack of additional triggered tremor beneath the San Gabriel Mountain in Southern California indicates that near-lithostatic fluid pressure is necessary but not sufficient for tremor to occur. We also extract individual low-frequency earthquakes (LFE) within the triggered tremor along the San Jacinto fault (SJF) and then perform matched-filter detection of additional LFE. However, we did not find clear evidence of repeated LFE over the time windows of the 2002 Denali Fault earthquake and other time where ambient tremors were suggested. Thus the tremor along the SJF is rare and the source depth is not well constrained, given the limited number of LFE.
Intellectual Merit Our research contributes to SCEC's research objectives on "regional search for seismic tremor at depth in Southern California". An improved understanding of tremor activity could help to better understand fundamental fault processes at the deep roots of plate-boundary faults.
Broader Impacts We are in the process of developing an online tutorial on triggering and detection of earthquakes/tremor. We will release it to public when ready. An draft version is online at http://geophysics.eas.gatech.edu/people/zpeng/Teaching/Triggering_Tutorial/
Exemplary Figure Figure 2: An example of waveform detection using a LFE template (red). In the left panel, continuous data is shown in black. Time is set in reference to the origin time of the 2002 Denali Fault earthquake. On the right panel, a zoom-in plot of the template (red) and detected event (blue).