The recent 4.4 magnitude earthquake near Decatur that was felt in Oak Ridge, and other reported earthquakes since then, made us wonder: How common are earthquakes in the area?
Minor earthquakes, those that can’t be felt, are fairly common, according to a customized search of data available through the U.S. Geological Survey.
But with one exception, all of the earthquakes were 3.0 magnitude or less. Earthquakes that weak are generally not felt.
The 4.4 magnitude earthquake about 11 kilometers north-northeast of Decatur on December 12 was the largest in that three-year group of earthquakes. It was the second-strongest recorded in East Tennessee. People reported feeling it in Oak Ridge and other communities across Tennessee, North Carolina, and Georgia.
A 4.4 magnitude earthquake is considered a significant earthquake.
In the past three years, there have been smaller earthquakes near Oak Ridge, Clinton, Coalfield, Farragut, Gatlinburg, Kingston, Knoxville, Lenoir City, Loudon, Maryville, and Sevierville. But the earthquakes have all had magnitudes of less than 3.0.
The time range we selected for our search was between January 1, 2016, and part of the day January 4, 2019. We searched for earthquakes between 0.5 magnitude and 7.0 magnitude in this area.
A previous earthquake felt by Oak Ridge residents occurred on November 10, 2012. It measured 4.3 on the Richter Scale, and it struck west of Whitesburg, Kentucky, shaking homes from Cincinnati to Atlanta. The epicenter was in southeastern Kentucky about 96 miles north-northeast of Knoxville.
At the time, USGS Geophysicist Paul Caruso said a 4.3-magnitude earthquake could cause chandeliers to swing and books to fall off shelves near the epicenter, but he wouldn’t expect any major casualties or major damage. They generally occur in quakes with a magnitude of 5.5 or greater, Caruso said.
The USGS says earthquakes do not occur frequently in most of North America east of the Rocky Mountains, but they are typically felt over a much larger region than they are in the West. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, the USGS said.
“However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake,” the USGS said.
Outside of East Tennessee, in just the past day, there were 16 earthquakes of 2.5 magnitude or greater in the United States or U.S. territories, according to USGS information available Sunday evening. There were 48 such earthquakes around the globe.
See our customized three-year search map here.
See regional USGS earthquake information here.
More information will be added as it becomes available.
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