CHARLOTTE, N.C. — Two earthquakes were reported near Greensboro early Tuesday. Both registered magnitudes slightly greater than 2.0.
The first happened at 2:19 a.m. in northeast Greensboro near U.S. 70 and Interstate 785. It registered a magnitude of 2.3, according to the United States Geological Survey.
The second earthquake happened a few minutes later in the same area. It registered a magnitude of 2.2, according to the USGS.
Typically a 2.0 earthquake is strong enough to be felt but not strong enough to cause any harm or damage. At this time, there has not been any reported damage.
Earthquakes are possible in the Carolinas. Weak earthquakes like this happen a handful of times each year. Stronger ones are less common.
"North Carolina is also earthquake country," Dr. Wendy Bohon, an earthquake geologist, told the Carolina Weather Group podcast. "There have been at least 23 times since 1935 that earthquakes have caused damage in North Carolina."
A 2020 earthquake in Sparta, NC, registered a magnitude 5.1 in Alleghany County. The earthquakes damaged roads and homes. The shaking was felt as far away as Charlotte.
In South Carolina, repeated earthquakes have occurred near Elgin over the past few years.
The unusual activity in South Carolina began on December 27, 2021, with a 3.3 tremor struck. The largest of the quakes happened on June 29, 2022 when a 3.6 was recorded just hours after a 3.5 took place that same day. The 3.6 quake was the strongest in South Carolina in the past eight years.
Experts said the quakes were part of a swarm that appears to be the longest in the state's history. What caused the swarm still hasn't been definitively determined. Last year, the South Carolina Department of Natural Resources released a report that suggested nearby Lake Wateree could be responsible. They believe the initial earthquake may have allowed water from the Wateree River to seep into new cracks that opened from the original December earthquake, which set off additional tremors in the area.
Earthquakes happen throughout South Carolina but mostly occur near the coast. Approximately 70% of South Carolina earthquakes are in the coastal plain region near the shore.
Back in 1886, Charleston was hit by a catastrophic earthquake. It had an estimated magnitude of 7.3 and was felt as far away as Cuba and New York. At least 60 people were killed and thousands of buildings were damaged.
“A number of old fault zones here," Del Bohnenstiehl, a North Carolina State University professor of earth science, explained to WCNC Charlotte's KJ Jacobs earlier this year. "We call it plate boundary hundreds of millions of years ago. And so, there are some relic fault zones from that can get reactivated from time to time.”
Bohnenstiehl said earthquakes are uncommon in both South Carolina and North Carolina.
“We’re not on what we would call a plate boundary. Think of the out parts of the earth on a ridge of blocks, and some places are rubbing past each other. We’re sort of in the middle of a block here,” Bohnenstiehl said.
On average, there are between ten and 20 earthquakes in South Carolina a year, according to Bohnenstiehl. Last year, the number climbed to over 80 because of the activity near Elgin.
That’s approximately 55 earthquakes per day worldwide.
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