Magnitude-4.0 quake rattles northern California

A shake map released by the US Geological Survey (USGS) on Aug 17, 2015 shows the location of a 4.2 magnitude earthquake, close to San Francisco, USA.
A shake map released by the US Geological Survey (USGS) on Aug 17, 2015 shows the location of a 4.2 magnitude earthquake, close to San Francisco, USA.PHOTO: EPA

OAKLAND, California (Reuters) - A small earthquake shook northern California on Monday, delivering a "quick, short shake", according to a Reuters witness in Oakland.

The United States Geological Survey registered the quake at magnitude 4.0 on the Richter scale, centered 1km north of Piedmont.