About earthquakes in the Easter Tennessee Seismic Zone:
The Eastern Tennessee seismic zone extends across Tennessee and northwestern Georgia into northeastern Alabama. It is one of the most active earthquake areas in the Southeast. Although the zone is not known to have had a large earthquake, a few earthquakes in the zone have caused slight damage. The largest known (magnitude 4.6) occurred on April 29, 2003, near Fort Payne, Alabama. Earthquakes too small to cause damage are felt about once a year. Earthquakes too small to be felt are abundant in the seismic zone, and seismographs have recorded hundreds of them in recent decades. Earthquakes in the central and eastern U.S., although less frequent than in the western U.S., are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).