A 4.5-magnitude earthquake centered just northeast of Yorba Linda struck around 11:20 p.m. Tuesday night.
About a minute later, a second, smaller quake hit in the same location. That tremor registered 2.7.
The first quake was felt from Azusa to San Diego, according to the U.S. Geological Survey. Although initially pegged at 4.4 on the Richter scale, it was later upgraded to a 4.5.
For residents in North Orange County, the quake was felt as a sharp jolt or long shake, but South County residents reported more of a mild rolling temblor.
No injuries or damage have been reported yet.
To learn whether the recent quakes could foreshadow a Big One, .