A magnitude 5.1 earthquake struck near Seven Trees, California, the United States Geological Survey (USGS) said.
The earthquake occurred 14 km east of Seven Trees near San Jose, the center of Silicon Valley, and the epicenter is 6.9 km.
It occurred at 11:42 a.m. on the 25th (based on the western United States), and an aftershock of magnitude 3.1 occurred 5 minutes later.
As a result of the earthquake that day, not only Silicon Valley, but also San Francisco could feel the shaking of the building.
However, no damage has been reported so far.
(Photo = USGS homepage capture, Yonhap News)