Compact Seismicity Bursts Have Different Characteristics from Background Seismicity

Nicolas DeSalvio, Wenyuan Fan, Andrew Barbour, & Jeanne Hardebeck

Published March 24, 2026, SCEC Contribution #14199

Earthquakes tend to cluster, developing into sequences driven by stress perturbations and transient fault-zone processes. However, these driving processes are difficult to observe or distinguish at high resolution because of their variability. Here we systematically identify seismicity bursts throughout southern California using new statistical methods and examine their causes with other independent geophysical observations. We find frequent seismicity bursts across southern California. These seismicity bursts are highly compact in space and time, showing low b-values, low stress drops, and varied stress ratios compared to background seismicity. These findings suggest that seismicity bursts are driven by transient processes acting frequently across the fault networks. The seismicity bursts can provide a new dynamic window into resolving short-term earthquake nucleation processes.

Citation
DeSalvio, N., Fan, W., Barbour, A., & Hardebeck, J. (2026). Compact Seismicity Bursts Have Different Characteristics from Background Seismicity. Journal of Geophysical Research: Solid Earth,. https://doi.org/10.1029/2025JB032917. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JB032917