Earthquake experts say the ground-shaking felt in Dalton, Ga., Wednesday morning was a 2.7 earthquake centered 1 mile west and southwest of the city.
Residents of Whitfield and Catoosa counties reported the earth shaking at about 11:45 a.m.
Crystal Paulk-Buchanan, spokeswoman for the Georgia Emergency Management Agency, said authorities first thought the tremors might be mild aftershocks from an earthquake this morning in Dyersburg, Tenn.
But reports and seismic data analyzed by the earthquake experts later found the event to be a separate and more powerful earthquake. The Dyersburg quake, a magnitude 2.5, occurred at about 6:35 a.m. about 5 miles north of Dyersburg and 76 miles northeast of Memphis.
In Dalton, no damage was reported, but officials did evacuate the courthouse for a brief time.
Jenny Crisp, an assistant professor of English at Dalton State College, said she heard a loud bang and then saw the windows rattle.
"It was a bit startling," she said. "Several of us thought, 'Is there a quarry nearby for blasting?'"
The trembling was not strong enough to shake anything off shelves or cause damage, Crisp said.
"Mostly we were just shaken up," she said.
The Tellus Science Museum provided a seismograph showing an earthquake centered near Dalton and about 3 to 5 miles deep.
Tellus Curator Julian Gray said the area is criss-crossed with ancient fault lines created when the Appalachian Mountains were formed. While the faults are not the same type as those in California, Japan and Turkey, they are prone to rumble fairly often.
Gary Patterson with the Center for Earthquake Research and Information in Memphis said the quake and faults are part of the East Tennessee Seismic zone, the second most-active earthquake zone in the eastern portion of the U.S.
"This zone stretches over about 200 miles and has about 80 earthquakes a year," he said.
It's not the first time North Georgia residents have felt the ground tremble.
On Jan. 5, 2010 a quake registering 2.6 magnitude rattled LaFayette, Ga. around 7:20 a.m.
On May 23, 2010, a 1.5-magnitude quake hit the outskirts of Dalton.
On June 23, 2008, the USGS Reported a 2.8-magnitude quake centered about 13 miles northeast of Dalton.
The East Tennessee Seismic Zone's largest recorded earthquake is a 4.6 that occurred in Fort Payne, Ala., in 2003.