Rumbling returns to South Carolina as recent flurry of earthquakes continues

The flurry of earthquakes in South Carolina continued Tuesday, as rumbling returned to a part of the state that has experienced lots of seismic activity in the past week.

A 1.5 magnitude earthquake was confirmed early Tuesday morning in the Greenwood County area, according to the U.S. Geological Survey. This is the 10 ^th consecutive earthquake recorded in South Carolina to hit in that area since tremors were confirmed Oct. 10.

On Sunday, eight more earthquakes were confirmed in Greenwood County, with seven of them in Coronaca, according to the South Carolina Department of Natural Resources Geological Survey.

Tuesday’s earthquake was recorded at 7:13 a.m. in the area near Coronaca, the South Carolina Emergency Management Division said. It happened just below the surface of the ground, the USGS said.

All of the recent seismic activity has coincided with S.C. Earthquake Preparedness Week , according to the state’s Emergency Management Division.

This was the 26 ^th confirmed earthquake this year in South Carolina, 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 64 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 Tuesday morning’s earthquake can report it to the USGS.

The most recent earthquake means at least 130 have been detected in the Palmetto State since the start of 2022, according to South Carolina DNR. All but 25 of the quakes have been in the Midlands.

In all, 111 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 Tuesday 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 144 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