A second earthquake in the same day rattles the South Carolina Midlands

For the second time in the same day this weekend an earthquake rumbled through the Columbia area.

A 1.3 magnitude earthquake was recorded Saturday night in the Midlands, according to the U.S. Geological Survey. The earthquake hit about 14 hours after tremors had rattled the same part of the Midlands.

The second earthquake was confirmed at 11:40 p.m. near Elgin, the South Carolina Emergency Management Division said. That’s in Kershaw County.

The Saturday night earthquake happened about a mile beneath the surface, according to the USGS.

The Saturday morning earthquake was a 2.83 magnitude event that happened at 9:27 a.m. about 1.75 miles beneath the surface, the USGS reported. It was slightly south of where Saturday night’s tremors were recorded, but still in the Elgin area, according to the USGS.

The second quake was the fourth confirmed earthquake this year in the state, after 28 quakes were recorded in 2023, according to the state Department of Natural Resources.

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 58 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 Saturday night’s earthquake can report it to the USGS.

The most recent earthquakes mean at least 108 have been detected in the Palmetto State since the start of 2022, according to South Carolina DNR. All but 10 of the quakes have been in the Midlands.

In all, 103 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 Saturday night’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 122 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 last December 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” last year, leaving some residents feeling uneasy.

The series of quakes might be thelongest 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