Tennessee's 4.1 magnitude earthquake awakened families and rocked the house to Atlanta Saturday morning as tremors spread across the southern U.S. No immediate report of any harm or significant damage.

The USGS website says the earthquake originated shortly after 9 a.m. ET, about 12 miles (20 kilometers) from Greenback, Tennessee, which is 30 miles (48 kilometers) south of Knoxville.

USGS spokesman Ayesha Davis received more than 23,000 public reports from USGS within the first hour of the earthquake. Meteorologists from TV News, which serve Georgia and North Carolina, reported the tremor.

According to USGS, there is a 5% chance next week with a 5% chance of 4 or greater aftershocks.

Gabriela Reilly is making waffles with her husband while shaking the entire house in Braselton, Georgia, which is northeast Atlanta.

"Our ceiling fans started to tremble for about 10 seconds," she said. "I thought a giant plane was flying low on a nearby plane, but my husband said, 'No, that was definitely an earthquake.'"

Jason Pack felt the walls shaking while he was still lying in his bed at home outside Knoxville, hearing the rumbling sounds enough to wake up his family and dogs to start barking.

“In East Tennessee, you’re used to tornadoes and flooding,” Pack said. “It’s unusual to have an earthquake.”

Pack has experienced tremors before, although it is probably the strongest he has ever felt in Tennessee.

"Even if it's small, it's a good reminder - if it's a big earthquake, would you know what to do? If you're inside, drop it, cover and hold it," said retired FBI agent Pack, who is now engaged in crisis communication. “If you’re outside, stay away from the building.”

According to the USGS, damage usually does not occur until an earthquake reaches a size of 4 or 5, although it depends on variables such as building, soil and distance from the center.

Davis said the southeastern U.S. has a huge earthquake risk, especially near the New Madrid earthquake zone in the west and the eastern Tennessee earthquake zone, where the earthquake occurred on Saturday.

Davis said that since 1950, other magnitude 4 or greater earthquakes have occurred within 155 miles (250 kilometers) of Saturday's earthquake. The largest of these was the 4.7-magnitude earthquake near Knoxville in November 1973.

Recently, in December 2018, two tremors hit the earthquake zone. One was a magnitude 4.4 earthquake centered on Decatur, Tennessee, south of Knoxville. It shocked homes as far as Atlanta.

A few days later, another earthquake hit a magnitude of 3.0. Its center is about 2 miles (4 km) southeast of Mascot, near Knoxville. This is also felt in parts of Georgia, Kentucky and North Carolina.

Davis said that due to the geology of the region, seismic waves from earthquakes spread more efficiently in the eastern U.S. region.

"The earthquake in the east was felt at a greater distance," she said.