SAN FRANCISCO—On Friday, December 19, a Bay Area earthquake occurred with an epicenter in Alcosta Boulevard and Bollinger Canyon Road in San Ramon.
The earthquake rattled the inhabitants in the East Bay, which included Danville, Dublin, Pleasanton and Hayward. People who live as far as San Francisco and San Jose felt it as well, but there were not any reports of any injuries to any individuals or damage to any property.
BART ran at a reduced speed for precautionary sake until 8:41 p.m., when it resumed as normal. Historically speaking, San Ramon last had an earthquake swarm in 1970, 1990 and 2015.
From 7:57 p.m. to 8:15 p.m., there were a number of aftershocks occurring after the main earthquake. At 8:36 p.m., the magnitude of the micro-earthquake was 2.1, centered three miles north of Dublin, California. By 8:15 p.m., the magnitude of the earthquake was 2.3. At 8:10 p.m., the magnitude was 2.9. At 7:57 p.m., the magnitude was 3.1.
At 7:56 p.m., the largest earthquake sequence in the range of the magnitude was 4.0, which occurred three miles southeast of San Ramon. At 7:49 p.m., an earthquake occurred which initial reports said it was a magnitude of 3.6 or 4.0 . At 7:41 p.m., the swarm began with a magnitude of 2.5 earthquake.
