Recent TN Earthquakes Shouldn’t Be Cause for Concern

A recent increase in the number of earthquakes registered across the state of Tennessee shouldn’t be cause for concern.

That according to Dr. Bob Hatcher, Structural Geology and Tectonics Professor Emeritus from the University of Tennessee – Knoxville.

“These… earthquakes do not occur on a single line, so we don’t think it’s activity along a single fault. So we can’t relate it that way,” Hatcher said. “If they were on a single fault, then there could be reason for concern and these could be foreshocks. But as it stands now, they’re distributed over a wide area over east Tennessee and the Shelbyville one is not connected at all.”

At least 24 earthquakes have occurred in Tennessee since the beginning of December, according to the United States Geological Survey.

However, Hatcher said the most recent earthquake just outside Shelbyville stands out from the rest.

“Those in east Tennessee are part of the East Tennessee Seismic Zone. The one in Shelbyville is not in East Tennessee, and it’s not in the west Tennessee New Madrid Zone,” Hatcher said. “So it’s sort of an oddball that it sits out there. Why we had an earthquake out there, we have no idea except for the fact that all earthquakes are produced by elastic rebound along an active fault.”

Hatcher said it’s unclear what will happen during the rest of 2019 and beyond as far as earthquakes go as researchers still aren’t able to predict when one will occur.

“We could continue to have small earthquakes throughout 2019, or we could have none. But we always have some very small earthquakes in east Tennessee,” Hatcher said. “We don’t necessarily expect there to be any larger earthquakes but we don’t know this. We don’t have the ability to predict earthquakes. That’s simply not within the technological capabilities of our science at this point.”

Hatcher said earthquakes aren’t uncommon in Tennessee with research suggesting seismic activity in the region dating back 10,000 years, with the Madrid Zone having major quakes every 400-600 years.

Nearly half of all Tennessee earthquakes since December have occurred near Decatur, including a 4.4-magnitude quake on Dec. 12. Hatcher said many of those were likely aftershocks from larger quakes as most registered less than 2.0-magnitude.