Although Tennessee is in the middle of North America, we are still affected by tectonic activity. There are earthquakes in this region from time to time, thanks to the New Madrid Fault.
This Tectonophysics article helps us understand why there are earthquakes in Tennessee. North America began to rift, or break apart, in the Late Precambrian time. One arm of the attempted rift failed and has since been buried by hundreds of meters of sediment. Sometimes, the plates slip along this lingering deep fault and shake Tennessee and the surrounding states.
The New Madrid Fault is named after New Madrid, Missouri. This USGS article details the historic New Madrid Earthquakes of 1811 and 1812, which were famously large, most breaking a magnitude of 7 on the Richter Scale. The Fault hasn’t wreaked such havoc in the past two centuries, but it does cause a notable quake every once in awhile.