The epicenter was located about 5 miles east of Yorba Linda, in Orange County, and about 30 miles from Los Angeles.
The quake hit just after 5 a.m. local time and had a depth of about 2 miles.

There were no immediate reports of damage or injuries.
A number of people reported being jolted awake by the tremor in Southern California.
After 5 a.m. local time, a torrent of people tweeted about the quake.
Quakes on East Coast?
While most of North America east of the Rocky Mountains has infrequent earthquakes, there are hotspots of intense quake activity.
The USGS points out that while earthquakes east of the Rockies are less common than in the West, they are typically felt over a much broader region.
“East of the Rockies, an earthquake can be felt over an area more than ten times larger than a similar magnitude earthquake on the west coast,” the USGS says.
“It would not be unusual for a magnitude 4.0 earthquake in eastern or central North America to be felt by a significant percentage of the population in many communities more than 60 miles from its source. A magnitude 5.5 earthquake in eastern or central North America might be felt by much of the population out to more than 300 miles from its source.”