Seismicity bursts stand out from background seismicity in Southern California
Nicolas DeSalvio, Wenyuan Fan, Andrew J. Barbour, & Jeanne L. HardebeckSubmitted September 7, 2025, SCEC Contribution #14844, 2025 SCEC Annual Meeting Poster #TBD
Earthquakes tend to occur in sequences driven by stress changes and transient fault zone processes. However, these driving processes are difficult to observe or differentiate in high resolution because of their variability. This results in earthquake sequences with differing behaviors that may deviate from standard mainshock-aftershock and swarm categorizations. Here, we systematically identify seismicity rate anomalies, termed seismicity bursts, throughout southern California and investigate their causes using independent observations. We find that seismicity bursts occur frequently throughout southern California. These seismicity bursts are highly spatiotemporally clustered, have low Gutenberg-Richter b-values, have low stress drops, and have varied stress ratios compared to other earthquakes in the same locations. These observations suggest that seismicity bursts are driven by transient processes that act frequently across fault zones. The seismicity bursts can provide a new, high-resolution dynamic window into how fault zone processes evolve over time.
Key Words
seismicity, microseismicity, earthquake statistics, seismicity bursts
Citation
DeSalvio, N., Fan, W., Barbour, A. J., & Hardebeck, J. L. (2025, 09). Seismicity bursts stand out from background seismicity in Southern California. Poster Presentation at 2025 SCEC Annual Meeting.
Related Projects & Working Groups
Seismology