People in Piedmont, 13 miles east of San Francisco, were shaken out of their sleep on Monday morning by an earthquake of magnitude 4.2.
As per the U.S. Geological Survey the earthquake struck a mile north of Piedmont, California, at 6:49 a.m. PDT.
Train services including the Bay Area Rapid Transit briefly paused operations and resumed service by 7:25 a.m. PDT. It is a standard procedure for rail transport in times of natural calamities.
The loss had not been assessed as there were no reports of damage.
There were at least six aftershocks near Piedmont, all under 2.5 magnitude as per USGS report.