Monday’s earthquake — the seventh-strongest of the past 100 years in East Tennessee — measured 3.8 in magnitude and was centered 7 miles north of LaFollette, 20 miles beneath the earth’s surface.

First the ground rumbled, then social media lit up.

As earthquakes go, Monday’s was a relatively minor one — initially measured at a 3.6 magnitude by the U.S. Geological Survey before later being upgraded to a 3.8 magnitude quake. For East Tennessee, though, the strength of the earthquake was quite uncommon, even as earthquakes along the seismic zone that stretches across the state from Alabama to Virginia become more common.

The earthquake shook homes and rattled windows, and could be heard as well as felt. But there were no reports of damages, according to the USGS. 

The quake occurred shortly after 2 p.m., near Fincastle, Tenn. — or just about seven miles north of LaFollette, just off S.R. 63. 

In Oneida, some 27.5 miles west as the crow flies, the earthquake could easily be felt. Many Scott Countians took to social media on Monday afternoon to express their surprise at the sudden jolt of the earth. 

While some were slightly alarmed at the earthquake, most people had fun with it. Jeremy Cross posted a photo of himself and his dog, both wearing helmets, and captioning it: “We just felt our first earthquake. Athena and I are ready for the next one.” Others posted a meme of cheap, plastic lawn furniture overturned, with the caption, “Earthquake 2020: We Will Rebuild.”

Earthquakes are hardly uncommon. There were four in the continental U.S. on Monday alone. And when they occur in the eastern U.S., they tend to be felt across a larger area than in the western U.S., because the rock beneath the surface of the earth is more hardened, allowing the seismic energy of the shifting plates to travel further.

While most earthquakes occurring in the East Tennessee Seismic Zone are too small to be registered — generally less than 2.5 magnitude — minor earthquakes are becoming increasingly common. There have been 12 in the East Tennessee region in the past year alone.

But Monday’s quake was exceptionally uncommon. It goes down as the seventh strongest earthquake in East Tennessee in the last 100 years. It’s the strongest since a 2018 earthquake in Decatur, Tenn. that measured 4.4 magnitude.

Monday’s earthquake occurred some 20 miles beneath the earth’s surface, according to the USGS.

For perspective, the New Madrid earthquakes of 1811 and 1812, which caused Reelfoot Lake to form in West Tennessee, measured between 7.0 and 8.0.

Geologists have known for some time that the ground is particularly shaky in East Tennessee. In 2014, the USGS increased the earthqhake hazard for much of the East Tennessee region, particularly in the foothills of the Great Smoky Mountains, to the next-to-greatest hazard on its seven-step scale. Scott County and much of the Cumberland Plateau is in the fourth-highest step on the scale. 

However, the hazard risk in East Tennessee remains far lower than the New Madrid Seismic Zone in West Tennessee, along with parts of Missouri, Arkansas, Kentucky and Illinois.

There have been more than 150 earthquakes in East Tennessee since the mid 1970s. The 4.4 magnitude earthquake in Decatur was felt as far away as Atlanta, but there have been larger quakes close to home in years past. There was a 4.7 magnitude earthquake in Maryville on October 30, 1973, and a 5.9 magnitude quake in Knoxville on March 28, 1913. 

The USGS estimates that damages do not typically occur unless an earthquake has a magnitude in the upper 4s or greater than 5.0.