Science2016-2019Southern Californiahigh confidence

Researchers identified 22,698 earthquakes in the Cahuilla swarm in Southern California, which lasted nearly four years.

Notes on verification

Multiple independent outlets (Caltech, ScienceNews, ScienceDaily, Phys.org, National Geographic) corroborate the ~22,000+ earthquake count and roughly four-year duration; the exact 22,698 figure matches secondary reporting derived from the primary study. [tier=silver indep_score=0.833 clusters=3 claim_tier=notable]

Sources