A series of small earthquakes have struck along the U.S. west coast, sparking fears a bigger tremor might be on the way.
A three-point-three magnitude quake was recorded in Alamo, some 48 kilometers from San Francisco, on Monday.
It followed three small tremors that were recorded in Danville the day before and the U.S. Geological Survey continued to record smaller tremors.
There have been no reports of injuries or damages yet, though rail services were slowed as a precaution.
Residents in California are worried the swarm of small tremors may signal that a bigger quake is coming, but the USGS says that is unlikely to happen.
