A small earthquake shook northern California, delivering a "quick, short shake," according to one witness in Oakland.
Reuters said the US Geological Survey registered the quake at magnitude 4.0 on the Richter scale, centred one mile north of Piedmont.
According to the USGS, the quake was felt most strongly on the East Bay, including Oakland, Berkeley and surrounding areas. Lesser shaking was felt in San Francisco.
While there were no immediate reports of damage or injury, one weatherman was certainly put off his stride by the tremor.
Oakland weatherman as this morning's #earthquake struck: "Oh my goodness. Oh my goodness. This is a good one." http://t.co/fzg6HOPLX3
— Mashable (@mashable) August 17, 2015
Reaction of pups caught on surveillance video during this morning's #earthquake is PRICELESS! http://t.co/lsFOVMA0kZ pic.twitter.com/7Ns4adQOj0
— 997 NOW (@997now) August 17, 2015
This map shows exactly where the earthquake struck.
http://t.co/wRP3g0y3Bv Map by USGS shows the epicenter of this morning's earthquake was just east of San Francis… pic.twitter.com/l6WilSV6Fb
— Mr. Better Credit (@MrBetterCredit) August 17, 2015
California has 23.4 per cent of all earthquakes in the US and has reported more than 6,500 in the past year.
The largest one in the last 12 months was a 6.0 magnitude quake in American Canyon in August when a tsunami bulletin was issued.
Bay Area Rapid Transit is holding trains to check the tracks on the public transit system. Commuters should expect delays.
