Recent swarm of earthquakes in Lake Murray area is part of a larger spike in SC

About a quarter past noon on Feb. 26, social media lit up with chatter about an earthquake that had just struck the Columbia area. Multiple people said their houses shook from the tremor, some reported hearing a booming sound, others shared videos of swaying furniture from their home surveillance cameras.

The magnitude-3 earthquake was minor and harmless — what’s typical in South Carolina — but it was the strongest to have struck the Midlands in over a decade, U.S. Geological Survey records show.

It was also among five earthquakes centered on the eastern banks of Lake Murray within a span of less than three weeks, reflecting a spike in Midlands earthquakes since 2021, The State found after analyzing USGS data in the past quarter-century.

In the five years since March 2021, according to the data, the Midlands has experienced 19 earthquakes with magnitudes of at least 2.5 (the threshold where seismometers can detect all earthquakes, and year-by-year comparisons are reliable).

By contrast, there were only six such Midlands earthquakes from 2000 to 2020, whereas 19 occurred in the Lowcountry and 15 in the Upstate.

Most of the recent Midlands tremors are part of a “swarm” between Elgin and Lugoff, a series of minor earthquakes in a confined location that does not follow a big quake.

Scientists now say the same phenomenon is happening in the Lake Murray area, and the explanation still remains elusive.

“It looks like there is a small swarm there,” said Thomas Pratt, a USGS research geophysicist and coordinator of the federal bureau’s earthquake hazards program in the central and eastern states.

“It’s kind of a mystery why we get earthquakes in the middle of this stable boundary,” he said, referring to the lack of major fault lines in the eastern United States. “We cannot predict whether it will continue, die out or lead to something larger.”

Pratt said certain industrial activities — such as fracking and filling a water reservoir — can trigger earthquakes, since they generate water pressure that lubricates the earth’s tectonic faults and pushes them apart. Reduced friction allows the faults to slip, releasing energy that travels through the earth’s crust and causing tremors.

The release of energy also produces an accompanying noise, said Scott Howard, South Carolina’s state geologist, with the Department of Natural Resources.

“This transition from rock to air causes just like a booming sound,” Howard said. Some people have described it as a rumbling noise, similar to a moving train or large truck.

Researchers from the University of South Carolina, College of Charleston and Georgia Institute of Technology are studying the Elgin-Lugoff swarm, seeking to understand its cause.

The geologists are exploring whether the swarm is somehow linked to the nearby Wateree River, such as the body’s changing water levels and rainfall in the area.

Pratt does not think human activity has triggered the recent Columbia-area earthquakes. He has reviewed the changes in water levels at Lake Murray, a reservoir, and believes they have been too small to induce earthquakes.

“Why would there not have been earthquakes during earlier water-level changes?” he said.

No one can predict when or where earthquakes will happen, or how powerful they’d be. But, geologists said, massive ones are rare in South Carolina. The strongest ever recorded in the state — as well as on the eastern seaboard — was a 7.6-magnitude earthquake that struck Charleston in 1886 and killed around 60 people.

Minor earthquakes, experts said, should remind residents to have an emergency plan and supplies in place. These include figuring out in advance how to communicate with family members in case of a major natural disaster.

If a strong earthquake occurs, and objects or building materials begin to fall, seek cover under a desk or table and hold on to it. Try to remain indoors, staying clear of hazardous areas such as windows and kitchens.

People should not run outdoors, since they might trip, bang into things or get hit by debris.

“What kills people are falling objects,” Pratt said. “Earthquakes don’t kill people.”

This story was originally published March 9, 2026 at 5:00 AM.