November 21, 2010
By Caroline Zilk
Arkansas Democrat-Gazette
GUY — Last year at this time, the Arkansas Geological Survey had recorded about 35 earthquakes. This year there have been more than 400, and several have been felt by Faulkner County residents.
Generally, earthquakes below a magnitude of 2.5 are not felt by residents in the area, and many of the smaller earthquakes are now being detected by a new system installed in March of this year at Woolly Hollow State Park.
Photo: Scott Ausbrooks, a geologist for the Arkansas Geological Survey, downloads monthly data from a seismic station to his laptop on a Faulkner County farm. Ausbrooks monitors many such stations in the region. (Thomas Hudson / Staff Photographer)“We can detect earthquakes with magnitudes of 1.5 and maybe even as low as a 1 in ideal circumstances,” Scott Ausbrooks, director of the Arkansas Geological Survey, said in a June interview with the River Valley and Ozark Edition.
This summer, Ausbrooks and his team were unsure if the low magnitudes of earthquakes were normal seismic activity in the area that had previously been undetected because of the lack of a seismic network.
About six months later, the survey is still unsure of the cause of the quakes, and residents near Guy, where most of the quakes are centered, are becoming concerned.
The largest earthquake detected so far was a 4.0 magnitude on the morning of Oct. 11, and smaller earthquakes continue to be detected on a regular basis.
Despite Ausbrooks’ promise that a larger earthquake is extremely unlikely in the Faulkner County area, residents still aren’t convinced.
To answer questions and address concerns, the survey, the Arkansas Oil and Gas Commission and the Faulkner County Office of Emergency Management teamed up to present an informational seminar for Faulkner County residents on Nov. 9 at Guy-Perkins High School.
Ausbrooks, who lives in Wooster, appealed to the attendants of the meeting as a neighbor. He presented an informational session he calls “Earthquakes 101,” which explains why earthquakes happen and the geology of the state of Arkansas.
He promised that further testing would occur to determine the cause of the earthquakes, but many Faulkner County residents have their minds made up.
“Everybody that I’ve talked to? We strongly believe that the cause of the earthquakes is the rigs and the oil and gas companies,” said Lacey Wilson of Guy.
Wilson has a 2-year old son, who she said has been awoken consistently by the quakes.
“Every time he feels an earthquake, he says, ‘Whoa!’ So I know he’s feeling them, too,” she said.
At the meeting, Wilson sat up front and took advantage of the opportunity to state her opinion — loudly.
“I didn’t mean to yell,” she said later.
But during the meeting, Wilson raised her voice at Larry Bengal, director of the Arkansas Oil and Gas Commission.
“We need to get together as a community because if the earthquakes continue to get strong, it’s going to be homes ruined and possibly people’s lives,” Wilson said. “I have a child I’ve got to worry about.”
Applause followed her comments.
Ausbrooks and Bengal said no new injection wells will be drilled in the area until gas drilling has been ruled out as the cause of the quakes.
Studies will be conducted in the area to find out if the magnitude of the quakes has anything to do with the gas drilling.
Ausbrooks hopes to have data from the studies by early next year.
“At this time, we don’t see any relationship between the earthquakes and the production wells, and that includes fracking,” Ausbrooks said. “What we haven’t ruled out is the disposal wells.”
Ausbrooks said he is aware that people are passionate about all aspects of the Fayetteville Shale play.
“Folks had some really good questions,” he said. “I hope we answered their questions and continue to do so in the months to come.”
For more information, visit www.geology.ar.gov.
http://www.arkansasonline.com/news/2010/nov/21/why-does-earth-quake/