More than 2 dozen quakes shake Arkansas in a week

LITTLE ROCK — More than two dozen earthquakes have rumbled through Arkansas in the past week.

Many of the temblors have been too small for people to notice, let alone cause injuries or property damage. But a couple of people reported feeling a 3.4 magnitude quake that shook an area north of Morrilton overnight Friday.

“It startles people,” said Johnathan Trafford, director of the Conway County Office of Emergency Management. “They’re not used to feeling the ground shake.”

The latest quakes — clustered in four areas of the state, including the one north of Morrilton — come two years after hundreds of temblors shook central Arkansas in what was known as the Guy- Greenbrier swarm.

The quakes near Guy and Greenbrier all but stopped after the Arkansas Oil and Gas Commission voted to ban wells for the disposal of natural gas drilling fluids in July 2011.

“In the Guy- Greenbrier swarm from fall 2010 to spring of 2011, we saw over 1300 earthquakes,” said Scott Ausbrooks, geo- hazards supervisor for the Arkansas Geological Survey. “Once they shut those wells done in July, that following year, we saw less than a dozen. ... If there wasn’t a correlation, then it would be an extraordinary coincidence.”

Ausbrooks said he believes some of the

recent quakes — including seven that shook east of Cave City on Tuesday and another near Blytheville — occurred naturally.

But it’s not clear whether the quakes north of Morrilton and in another area south of Clinton are also natural occurrences or whether something else is to blame.

Ausbrooks said there are three possible explanations for the quakes south of Clinton: They could be happening naturally, they could be triggered by a change in the level in a nearby lake or they could be tied to nearby wells that apparently weren’t covered under the 2011 moratorium.

“I’m not saying that’s it yet, but that is another possibility,” Ausbrooks said about two nearby injection wells.

Ausbrooks said the quakes north of Morrilton could be natural occurrences or they may be tied to injection wells, too, but the injection wells closest to the quakes are farther away than the ones near the quakes south of Clinton.

Lawrence Bengal, director of the Arkansas Oil and Gas Commission, didn’t respond to an email Friday.

Regardless of the cause, Ausbrooks said it’s unusual that four areas of the state would be seismically active simultaneously.

“The big question is: Have we seen the whole show or is this just the beginning?” Ausbrooks said. “We just don’t know yet.”