Posted: 4:56 a.m. | Updated: 4:20 p.m.

The earthquake that hit the Roanoke Valley early this morning was a magnitude 3.0, the U.S. Geological Survey is now reporting, and the epicenter was 3 miles from Roanoke.

Immediately after the quake, which was recorded at 4:08 a.m., the USGS originally said that it had registered at 2.6 on the Richter scale and that the epicenter was about 4 miles west-southwest of Roanoke, near the Cave Spring area. Later, the USGS reported that the quake was a 2.8.

An "overflow" of people have called 911 in Roanoke, according to emergency dispatchers, though no damage or injuries have been reported.

Earthquakes of this intensity usually do not cause much damage, the National Earthquake Information Center said. Sometimes called microearthquakes, they often are only detected by seismographs and not felt by people.

By 5 a.m., the Earthquake Information Center's Web site listed more than 100 reports of weak or light shaking in Roanoke, Vinton and Salem.