The Cahuilla earthquake swarm's earthquakes initially began about five miles underground after fluid entered a fault system and altered pressure within the rocks.
Notes on verification
Confirmed by peer-reviewed Science paper (Ross et al. 2020), Caltech press release, ScienceDaily, and ScienceAlert, all corroborating the fluid-injection mechanism and ~5 mile/8 km depth. [cascade flags: aggregator_dropped_primary_exists | tier=silver indep_score=0.95 clusters=3 claim_tier=notable] [llm_rejected_corroborator url=https://www.caltech.edu/about/news/natural-fluid-injections-triggered-cahuilla-earthquake-swarm] rejected by auto_resolver_v1_8 run=13071dc8: The page states that fluids entered the fault zone and triggered earthquakes but does not mention a depth of five miles or altered pressure within the rocks.
Sources
- A strange earthquake swarm lasted for years. Scientists finally know ... (seed:environment_and_wildlife)
- https://www.caltech.edu/about/news/natural-fluid-injections-triggered-cahuilla-earthquake-swarm (corroboration)
- https://www.science.org/doi/10.1126/science.abb0779 (corroboration)
- https://www.sciencealert.com/scientists-think-they-ve-explained-a-four-year-swarm-of-earthquakes-in-california (corroboration)