A 4.5 magnitude earthquake rocked California's Bay Area this week.
The epicenter of the seconds-long quake, which happened around 10:30 p.m. local time, was in the Pleasant Hill area, less than 30 miles from San Francisco, according to the US(CNN) - A 4.5 magnitude earthquake rocked California's Bay Area on Monday.
The epicenter of the seconds-long quake, which happened around 10:30 p.m., was in the Pleasant Hill area, less than 30 miles from San Francisco, according to the US Geological Survey.
But it could mean there's a heightened chance of a bigger quake over the next few days near the Calaveras Fault, a branch of the San Andreas Fault system, she said.
There's a 36% chance of aftershocks measuring magnitude 3 or higher in the week following the quake, most likely near the epicenter, the USGS forecasts.