The largest earthquake in the Cahuilla swarm occurred in August 2018, nearly three years after the swarm began, and measured magnitude 4.4.
Notes on verification
Multiple independent sources (Smithsonian, Science News, Caltech, USGS) confirm the 4.4 magnitude as the largest in the swarm; timing detail corroborated by original NatGeo reporting and consistent with swarm's known 2016 start date. [tier=silver indep_score=0.833 clusters=3 claim_tier=notable]
Sources
- A strange earthquake swarm lasted for years. Scientists finally know ... (seed:environment_and_wildlife)
- https://www.sciencenews.org/article/machine-learning-california-earthquake-swarm (corroboration)
- https://www.caltech.edu/about/news/natural-fluid-injections-triggered-cahuilla-earthquake-swarm (corroboration)
- https://www.smithsonianmag.com/smart-news/earthquake-swarm-reveals-complex-structure-california-fault-line-180975161/ (corroboration)