A pair of earthquakes struck eastern Tennessee today, adding to the overall number of earthquakes the state has seen in the last few weeks. According to USGS, the earthquakes struck 4 minutes apart from each other with the epicenter just 4 miles apart too. The first earthquake was recorded at 6:30 am from a depth of 13.9 km; it was rated a magnitude 2.4 event. The second earthquake struck at 6:34 am from a depth of 12.9 km; it was rated a magnitude 2.3 event. Both struck in southeastern Tennessee east of Chattanooga and south of Knoxville. These were the 30th and 31st earthquake to strike the state in the last 30 days.
USGS says that earthquakes with a magnitude of 2.0 or less are rarely felt or heard by people, but once they exceed 2.0 , more and more people can feel them. While damage is possible with magnitude 3.0 events or greater, significant damage and casualties usually don’t occur until the magnitude of a seismic event rises to a 5.5 or greater rated event.
Earthquakes like the one that hit last night in the eastern part of Tennessee are unlikely associated with the New Madrid Seismic Zone, an area of ongoing seismic activity located near the Mississippi River. However, while USGS says western Tennessee has a higher frequency of damaging earthquake shaking, the risk isn’t that low in eastern Tennessee. In the area of this most recent quake, USGS says its likely this area would see 50-100 damaging earthquakes over 10,000 years. While this number is low, it is much higher than it is elsewhere in the eastern half of the United States, where it’s likely to have 10 or less earthquakes over the same period.
The primary emergency advice for an earthquake in Tennessee is to “Drop, Cover, and Hold On” the moment one feels the ground shake. Because Tennessee sits directly between two active fault areas—the New Madrid Seismic Zone in the west and the East Tennessee Seismic Zone in the east—the Tennessee Emergency Management Agency (TEMA) emphasizes being physically and financially prepared for a sudden tremor.
According to USGS, the number of earthquakes in Tennessee is increasing over time. USGS says that the number of earthquakes in Tennessee hovered around just 30-50 per year during the mid-to-late 1990s. That number increased to approximately 150 in the mid-2000s and shot up to nearly 300 in the late 2010s.
