Overview
- USGS recorded a magnitude 3.0 quake at 8:14 a.m., followed by magnitudes 2.8 and 2.6 at 8:16 and 8:18 a.m.
- The epicenters were in a residential area just south of Bollinger Canyon Drive between Dougherty Road and Alcosta Boulevard.
- The bursts continue a swarm that began in November and has produced more than 300 earthquakes, including a magnitude 4.0 on December 19.
- Officials reported no injuries or structural damage from Friday’s shaking.
- San Ramon lies on the Calaveras Fault, and USGS scientists say the cause of these focused swarms is uncertain, noting similar sequences since 1970 have not necessarily led to larger earthquakes.