For the second time in less than a week, an earthquake hit South Carolina.

A 2.1 magnitude earthquake was recorded Sunday morning in McCormick County, according to the U.S. Geological Survey. Not only was it South Carolina’s second confirmed earthquake in a six day span, it also was recorded near the same part of the Palmetto State where the previous quake occurred.

Sunday’s earthquake was confirmed at 2:53 a.m. near Jackson, the South Carolina Emergency Management Division said.

The earthquake happened about half 3.5 miles beneath the surface, according to the USGS.

This was the 12^th confirmed earthquake this year in South Carolina, after 28 quakes were recorded in 2023, according to the state Department of Natural Resources.

The last time seismic activity was recorded in South Carolina was on Aug. 26, when tremors were recorded as a 1.9 magnitude earthquake hit in the Jackson area of Aiken County, state Department of Natural Resources data shows.

This was the first earthquake recorded in McCormick County since May 25, 2019, and it’s only the third time since 2006 that seismic activity has been confirmed there, according to the USGS.

History of earthquakes in SC

It has been uncommon for earthquakes to hit outside of the Midlands area of the Palmetto State, specifically beyond Kershaw County, where 62 earthquakes have been confirmed since the end of June 2022, according to the South Carolina DNR.

That’s also where South Carolina’s most powerful recent earthquakes were recorded on June 29, 2022.

On that day, two earthquakes — one a 3.5 magnitude and the other 3.6 — were included in a flurry of tremors and aftershocks. Those were the two largest quakes to hit South Carolina in nearly a decade. A 4.1-magnitude quake struck McCormick County in 2014.

Anyone who felt tremors and shaking or heard rumbling from Sunday morning’s earthquake can report it to the USGS.

The most recent earthquake means at least 116 have been detected in the Palmetto State since the start of 2022, according to South Carolina DNR. All but 13 of the quakes have been in the Midlands.

In all, 108 earthquakes have hit the Columbia area since a 3.3-magnitude quake was recorded Dec. 27, 2021, according to the DNR.

The S.C. Emergency Management Division said Sunday morning’s earthquake was classified as a micro quake, according to the Modified Mercalli Intensity Scale.

No major damage or injuries have been reported from any of the recent quakes.

Earthquakes that register 2.5 magnitude or less often go unnoticed and are usually recorded only by a seismograph, according to Michigan Technological University. Any quake less than 5.5 magnitude is not likely to cause significant damage, the school said.

It had been typical for South Carolina to have between six and 10 earthquakes a year, the S.C. Geological Survey previously reported. There have been 130 earthquakes in South Carolina since Jan. 18, 2021, according to DNR.

During a 2022 town hall to address the earthquakes, state geologist Scott Howard said as many as 200 smaller tremors might have gone unnoticed and unrecorded.

Why the increase in earthquakes?

An explanation for the outburst has eluded scientists.

Some experts have theorized there’s a link between the Wateree River and the earthquakes northeast of Columbia. They said the combination of a single moderate earthquake in December 2022 and high water levels in the Wateree River during parts of 2022 and 2023 have contributed to the earthquakes.

But no one has settled on the single cause for the Midlands’ shaking.

Elgin, about 20 miles northeast of Columbia and situated on a fault line, experienced an unusual earthquake “swarm,” leaving some residents feeling uneasy.

The series of quakes might be the longest period of earthquake activity in the state’s history, officials said. But they don’t believe the spate of minor earthquakes is an indicator that a bigger quake could be on the way.

“Though the frequency of these minor earthquakes may alarm some, we do not expect a significantly damaging earthquake in South Carolina at this time, even though we know our state had them decades ago,” South Carolina EMD Director Kim Stenson previously said in a news release.

“Now is the time to review your insurance policies for earthquake coverage, secure any items in your home that may become hazards during a tremor and remember to drop, cover and hold on until the shaking passes. These are the precautions South Carolinians can take to properly prepare for earthquakes.”

The strongest earthquake ever recorded in South Carolina — and on the East Coast of the United States — was a devastating 7.3 in Charleston in 1886.

That quake killed 60 people and was felt over 2.5 million square miles, from Cuba to New York and Bermuda to the Mississippi River, according to the state EMD.

Reported earthquakes in SC in 2021-24