If you thought you felt the ground move a bit shortly after lunch time on Wednesday, Sept. 13, it wasn’t your imagination.
An earthquake near the Virginia-West Virginia border was reportedly felt as far south as Asheville and the Triad area of North Carolina.
Multiple media outlets in the region reported individuals in North Carolina saying they had felt the quake, which measured somewhere between 3.2 and 4.0 on the Richter scale and occurred around 1:30 p.m.
Locally, at least two people responded to a Facebook post stating they had felt the quake.
Sue George, who lives in Mount Airy, said she felt the movement. Kathi Prescott, who also lives in Mount Airy, said she did as well, though she didn’t know what it was at first.
“I felt a light ripple under my feet in the afternoon,” she said in a Facebook message. “No windows shaking or things falling. Didn’t realize what it was until I heard on the news about a quake in Virginia. Wouldn’t have known otherwise what it was.”
A North Carolina Granite Corp. official said the seismograph there, however, showed no activity. “We didn’t register anything here,” he said by telephone. The official would not give his name and refused requests to transfer the call to someone who could talk more openly about what the seismograph may have registered.
“A lot of folks felt it,” said Martin C. Chapman, the director of the Virginia Tech Seismological Observatory in Blacksburg, Virginia.
While the U.S. Geological Survey labeled the quake as a 3.1 on its Richter Scale, Chapman said his department in Blacksburg — only about 30 miles from the epicenter of the quake — put the strength between 3.7 and 4.
Although he said it was the most powerful one in that region of Virginia since 1969, it didn’t cause any problems.
“It might have shaken some loose objects off of shelves. It’s conceivable near the epicenter you could have some chimney top damage, but that’s unlikely. I haven’t heard of any reports of that.”
Because it was a relatively deep quake — he put it at between 10 and 20 kilometers below the surface (6.2 to 12.4 miles), it was felt over a wide area.
“People probably felt it for more than 100 miles away,” he said, which would explain the reports in Mount Airy. Most people on the ground, however, would never have noticed.
“If you’re indoors and in the upper stories of a quiet wood frame building, you can feel the low frequency shaking, sort of like being on a boat in a pond and a wave comes along.”
He said the quake originated in what’s known as the Giles County seismic zone, where earthquakes are not uncommon.
“On May 31, 1897, there was an earthquake there with a magnitude greater than 5,” Martin said.
By comparison, the 5.8 earthquake in Central Virginia in 2011 was felt from New England through the midwest and as far south as Florida, with some levels of damage reported throughout the Mid-Atlantic states. Numerous people in Surry County reported feeling that quake.
Martin said quakes continued frequently in the Giles County, Virginia, region after the 1897 quake, though lessened over time. As recently as 1984, he said the area was still experiencing, on average, one every six months, and many of those were aftershocks of the 1897 quake.
He said it’s unclear if Wednesday’s earthquake was a separate event or yet another after shock from that 19th century earthquake.
Reach John Peters at email@example.com