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Tectonic tremor in the San Jacinto Fault, near the Anza Gap, detected by multiple mini seismic arrays

Alexandra A. Hutchison, & Abhijit Ghosh

Published August 15, 2016, SCEC Contribution #6928, 2016 SCEC Annual Meeting Poster #242

Using several detection and location methods, employing data from both network and mini high density seismic arrays, we detect several instances of non-volcanic tremor that are possibly located on the San Jacinto Fault (SJF) near the Anza Seismic Gap. We apply multi-beam backprojection [Ghosh et al., 2012], envelope cross correlation [Wech & Creager, 2008], spectral analyses, and visual inspection to the seismic array data from June 2011. Each location technique provides similar source locations for each of the tremor events in our catalog. Each event has been scrupulously tested with each of the methods, resulting in a conservative catalog. All of the tremor windows also have a low slowness, suggesting that they have a deeper source, ruling out potential sources of surface noise that may result in false detections. To further avoid such noise, we determine that the best frequency band to detect tremor in this region is 6-8 Hz, which ensures exclusion of the frequency band emitted by trains (3-5 Hz) [Cristea-Planton et al., 2013] that can often pollute the standard tremor frequency band of 2-8 Hz. These results indicate that stress dynamics and seismicity cycles in this section of the SJF may be affected by tremor and likely slow-slip, given their frequent coincidence in other areas.

Key Words
slow earthquakes, tremor, seismology

Hutchison, A. A., & Ghosh, A. (2016, 08). Tectonic tremor in the San Jacinto Fault, near the Anza Gap, detected by multiple mini seismic arrays. Poster Presentation at 2016 SCEC Annual Meeting.

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