U.S. Geological Survey teams have placed a seismic monitor in Conway County to record the earth’s movements in the area after a rash of more than two dozen earthquakes in five days.
The agency has recorded 28 earthquakes about 10 miles north of Plumerville since Thursday, including two 2.0-magnitude quakes Monday. The largest since Thursday has been a 3.4-magnitude temblor Friday.
There have been no reports of damage, and most quakes were not felt because they were small, said Scott Ausbrooks, geohazards supervisor for the Arkansas Geological Survey.
Two other earthquakes - a 2.3-magnitude followed by a 3.5-magnitude - rattled Conway County on March 22. Five quakes were recorded near Damascus in Van Buren County, and seven were recorded in Strawberry in Lawrence County on May 21.
Ausbrooks said it was rare for four areas of the state to be experiencing a series of quakes at the same time.
On Sunday, Ausbrooks and Steve Horton, a geologist with the U.S. Geological Survey in Memphis, placed monitor Station X106 in central Conway County near the quakes’ epicenters. Since then, the frequency of tremors has subsided, Ausbrooks said.
“It’s slowed down over the past 24 to 36 hours,” Ausbrooks said Tuesday afternoon.
Geologists are studying the quakes to determine if they are caused naturally or if nearby natural gas drilling operations are triggering the movements, Ausbrooks said.
The quakes are occurring along a bend in a fault system beneath Conway County that Ausbrooks said may be under stress. The fault makes a “V” near Plumerville, turning from the northwest to the northeast, he said.
The nearest gas drilling injection well is about eight miles to the northwest and may be too far away to cause the quakes near Plumerville, Ausbrooks said.
Natural gas injection wells caused hundreds of earthquakes in Faulkner and Conway counties two years ago, geologists said.
Ausbrooks said he thinks the latest series of quakes may be caused naturally and equates the rash of movements near Plumerville to the Enola Swarm, a series of earthquakes that rumbled beneath Faulkner County in 1982.
“We’re not completely sure, yet,” Ausbrooks said. “There’s no smoking gun there. We’re studying it.”
Plumerville Mayor Ed Paladino said residents in his town are taking the earthquakes in stride and are not worrying too much about them.
“You wonder what’s causing them,” he said. “But there’s not much talk yet. If this should continue and if they get bigger, then I think people will get concerned.”
Conway County Judge Jimmy Hart said he’s not felt any quakes at his home in the eastern end of the county.
“It does make you nervous,” he said of the temblors’ frequency. “It’s always a concern. We have a disaster plan in place for things like this.
“I’ve always heard that you have to take what Mother Nature gives you.”
Northwest Arkansas, Pages 9 on 05/29/2013