LITTLE ROCK — A 3.8-magnitude earthquake centered between Guy and Greenbrier Thursday marked the latest and one of the strongest of hundreds of quakes felt in the area in recent months.
Scott Ausbrooks, the geo-hazards and environmental geology supervisor for the Arkansas Geological Survey, said the Thursday morning rumbler was tied for third-strongest of more than 700 quakes in the region since September. More than 130 people reported feeling the quake on the U.S. Geological Survey website, including at least two reports from Missouri.
"It was like somebody ran a vehicle into your house is what it was like," said Ausbrooks, who felt the 4:49 a.m. quake in Greenbrier. "It was a quick jolt and a low rumble."
The 3.8 earthquake followed more than a dozen temblors Wednesday and was one of seven quakes in the area Thursday morning. The others Thursday all registered below a 3.0 while only one was larger than that Wednesday: a 3.5 quake recorded at 3:46 p.m.
There were no immediate reports of damage or injuries linked to any of the shaking, Ausbrooks said.
A 4.0 quake was reported in the same area last October and a 3.9 quake was recorded in November.
Small tremors have been felt in Faulkner County for months with geologists working to determine if the quakes are caused by natural events or man-made activities, such as saltwater disposal wells used by natural gas drillers.
Ausbrooks said officials with the geological survey are scouring data from wells in the Guy area, looking for a correlation between the amount of liquid injected into the ground, its pressure and the earthquakes. He said it's too soon to say if there is a connection.
"If you see something that looks like it may be correlating, you need to look at it over a period of time," he said. "At this time, we haven't seen anything that's 'oh, wow yes.' But what we're looking at is the trend."
The swarm of earthquakes near Guy since September in some ways mirrors a 1982 swarm near Enola, Ausbrooks said. In both cases, heavy seismic activity gave way to "lulls and spikes" in the numbers of quakes as time went on. There were relatively few small earthquakes in the several weeks preceding the outbreak of shaking that began Wednesday in the Guy-Greenbrier region.
But a pattern similar to the 1982 swarm - which occurred before there were any saltwater disposal wells - doesn't necessarily mean the earthquakes are natural.
"One part of me would say yes, it's good to see it follow a natural pattern," Ausbrooks said. "But the question is whether it's induced or not, is it still going to follow that pattern?"
This story was originally published at 6:17 a.m.