The earthquakes may be a long-lasting aftershock following a 3.3 magnitude quake in December
A series of 11 earthquakes have shook South Carolina particularly near the capital city Columbia over the past three weeks, and geologists are unsure of what – if anything – the quakes might mean for the area.
The seismic activity began on 27 December, after a 3.3 magnitude earthquake shook the border region between Richland and Kershaw counties.
Geologists believe that quake set in motion an extended period of aftershocks, which explains the recent spate of smaller quakes around the region.
Another quake, which was closer to Charleston, hit the area on Sunday. The 1.4 magnitude earthquake shook the region and was the fourth to hit the state in 2022.
South Carolina is no stranger to earthquakes. The state averages about 20 each year, as part of the state sits atop the Easter Piedmont fault system, which extends from Alabama north into Virginia. The fault system is ancient and likely formed around 480 million years ago, the same time the Appalachian Mountains rose.
While the ancient fault systems in the southeastern US have been largely inactive, Steven Jaume, an associate professor at the College of Charleston, told WYFF that the recent spate of earthquakes may indicate those faults are becoming active.
“The question is are those faults being reactivated,” he said. “Are they starting up again in that particular area? That’s what we’re investigating.”
In addition to the number of the quakes, the location is also unusual. Most of the state’s earthquakes occur near the coasts, particularly near the Charleston region. The recent group of quakes is much further inland, all occurring around Columbia.
Mr Jaume said that so long as the quakes continue to be minor, there is not likely cause for concern.
The last time the state suffered a major earthquake was 1886. That year, Charleston suffered the largest earthquake ever recorded in the southeastern US when a quake of at least a 7 magnitude rocked the city, leaving dozens dead and hundreds of buildings destroyed.
Prior to the quake, several smaller tremors occurred in the region over the course of several days. There was no way to know at the time that the quakes were foreshocks indicating a much large event to come.
Unfortunately, seismologists are still unable to forecast earthquakes. Unlike meteorology, which allows researchers to see storms and other weather events coming, there is no means of measuring data that could foretell the coming of an earthquake.
“You can’t see it coming,” Mr Jaume told The Associated Press on Wednesday. “There isn’t anything obvious moving or changing that you can put your finger on that you can say, ‘This is leading to this.'”