Two earthquakes have struck parts of the Western US state of California in an area notorious for seismic restlessness, the US Geological Survey says.
The first quake, measured 3.1 on the Richter scale, hit near San Martin in Santa Clara County on Tuesday night at 7:19 pm local time.
Almost three hours later at 10:32 pm, a stronger earthquake, measuring 3.9, struck about 8 miles east of the Alum Rock area of San Jose, at a depth of about 5.5 miles.
San Jose Mayor Sam Liccardo called on people via Twitter “to ready your home kit & be prepared” for quakes.
The tremor was widely felt throughout the San Francisco Bay Area.
So far, there has been no report of damage or injury resulting from the twin quakes.
The jolts were the latest in a series of sporadic quakes caused by the Calaveras Fault, which usually releases stress.
A 4.1 temblor hit in the same region last October. According to the USGS, there is a 7.4 percent possibility of a 6.7 magnitude or greater earthquake on the Calaveras Fault within the next 30 years, and a 14.3 percent likelihood on the Hayward Fault.
The Calaveras and Hayward faults are reportedly linked, meaning both could someday rupture together.
Earthquakes are fairly common in the region. This is the second in the last 10 days. In the past 30 days, nine quakes have been reported and in the last 365 days, 419 of magnitude 3.0 or greater occurred nearby.