USGS map shows the location of the earthquake.
A 3.5-magnitude earthquake struck Friday just over a mile from the Palomar Observatory in north San Diego County, according to the U.S. Geological Survey.
The quake occurred at 6:32 a.m. just over a mile south-southeast from the historic observatory on Palomar Mountain at a depth of five miles.
There are no reports of injuries or damage.
The USGS said the quake was felt as far south as Chula Vista and as far east as Oceanside.
City News Service contributed to this article.