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Abstract Oscillatory stresses are ubiquitous on Earth and other solid‐surface bodies. Tides and seasonal signals perpetually stress faults in the crust. Relating seismicity to these stresses offers fundamental insight into earthquake triggering. We present a simple model that describes seismicity rate due to perpetual oscillatory stresses. The model applies to large‐amplitude, nonharmonic, and quasiperiodic stressing. However, it is not valid for periods similar to the characteristic timeta. We show that seismicity rate from short‐period stressing scales with the stress amplitude, but for long periods with the stressing rate. Further, that background seismicity rateris equal to the average seismicity rate during short‐period stressing. We suggest thatAσ0may be underestimated if stresses are approximated by a single harmonic function. We revisit Manga et al. (2019,https://doi.org/10.1029/2019GL082892), which analyzed the tidal triggering of marsquakes and provide a rescaling of their seismicity rate response that offers a self‐consistent comparison of different hydraulic conditions.
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This content will become publicly available on July 1, 2026
False Positives in the Identification of Dynamic Earthquake Triggering
Abstract Dynamic earthquake triggering is commonly identified through the temporal correlation between increased seismicity rates and global earthquakes that are possible triggering events. However, correlation does not imply causation. False positives may occur when unrelated seismicity rate changes coincidently occur at around the time of candidate triggers. We investigate the expected false positive rate in Southern California with globalM ≥ 6 earthquakes as candidate triggers. We compute the false positive rate by applying the statistical tests used by DeSalvio and Fan (2023),https://doi.org/10.1029/2023jb026487to synthetic earthquake catalogs with no real dynamic triggering. We find a false positive rate of ∼3.5%–8.5% when realistic earthquake clustering is present, consistent with the 95% confidence typically used in seismology. However, when this false positive rate is applied to the tens of thousands of spatial‐temporal windows in Southern California tested in DeSalvio and Fan (2023),https://doi.org/10.1029/2023jb026487, thousands of false positives are expected. The expected false positive occurrence is large enough to explain the observed apparent triggering following 70% of large global earthquakes (DeSalvio & Fan, 2023,https://doi.org/10.1029/2023jb026487), without requiring any true dynamic triggering. Aside from the known triggering from the nearby El Mayor‐Cucapah, Mexico, earthquake, the spatial and temporal characteristics of the reported triggering are indistinguishable from random false positives. This implies that best practice for dynamic triggering studies that depend on temporal correlation is to estimate the false positive rate and investigate whether the observed apparent triggering is distinguishable from the correlations that may occur by chance.
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- Award ID(s):
- 2022441
- PAR ID:
- 10648617
- Publisher / Repository:
- AGU
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Solid Earth
- Volume:
- 130
- Issue:
- 7
- ISSN:
- 2169-9313
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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