San Ramon Swarm Produces 4.2 Magnitude Quake Monday
Tap title to read story
0:00 / 0:48
San Ramon, Calif. The U.S. Geological Survey reported a series of earthquakes struck the Tri-Valley area Monday morning, with a magnitude 4.2 temblor centered about 2½ miles southeast of downtown. The sequence began around 6:27 a.m., included multiple quakes between magnitudes 2.5 and 3.9, and culminated near 7:01 a.m.; agencies recorded between a dozen and dozens of tremors during a 30- to 90-minute span. BART slowed trains for track inspections; authorities reported no major damage or injuries. The USGS identified the event as part of an ongoing swarm that began in November. Based on 6 articles reviewed and supporting research.
More context
Timeline
- 1. Early November: USGS records an initial series of swarm earthquakes beginning Nov. 9.
- 2. Mid-to-late December: Area recorded dozens of small events; analysts tracked ongoing swarm patterns.
- 3. A two-week lull occurred before Friday when a 3.1 quake was recorded near San Ramon.
- 4. Monday morning: tremors began ~6:27 a.m., culminating in a 4.2 magnitude quake around 7:01 a.m.
- 5. Immediately after: BART slowed trains for inspections; authorities reported no major injuries and assessed minor property disturbances.
Sources
JQJO Editorial Desk · Human reviewed · AI assisted. Report a correction.
