Triggering of Deep Low-Frequency Earthquakes Along the Parkfield-Cholame Section of the San Andreas Fault by the 2019 M7.1 Ridgecrest and Other Recent Earthquakes

Session: Waveform Cross-Correlation-Based Methods in Observational Seismology [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

It is well known that distant earthquakes are capable of triggering deep tectonic tremor, mostly during the large-amplitude surface waves. However, the triggering pattern is less clear following local or regional earthquakes, partially because the frequency band of tremor overlaps with those of earthquakes. Here we examine tremor triggering behavior along the Parkfield-Cholame section of the San Andreas Fault following recent earthquakes in California. We primarily use the deep low-frequency earthquake (LFE) catalog detected by the 88 LFE template families using a matched filter technique, as well as visual inspection of high-frequency (> 20 Hz) waveforms during and immediately following earthquakes. We find that the 2019/07/06 M7.1 Ridgecrest mainshock triggered a few high-frequency tremor events at Parkfield during the first few cycles of its surface waves. However, unlike the 2014 M6.0 South Napa event, the 2019 Ridgecrest mainshock was not followed by a prolonged major tremor sequence in Cholame. This is likely because a major tremor sequence just occurred a few days ago before the Ridgecrest mainshock. Hence, the region may not be ready to be triggered by the Ridgecrest event. In addition, we find that a M4.3 local earthquake near Parkfield on 2019/12/17 triggered a one-hour episode of migrating tremor north of Parkfield, but it apparently did not trigger tremor in the Cholame region. Our next step is to re-examine the 19-year LFE catalog (since 2001) to identify how tremor behaviors in Parkfield change following local and regional earthquakes in California.

Presenting Author: Zhigang Peng

Authors