Geologist Answers Biggest Earthquake Questions
By: Jessica Dean
Updated: March 1, 2011
The morning after a 4.7 magnitude earthquake hit Faulkner County, geologists from the Arkansas Geological Survey were already at work trying to collect more data in order to determine exactly where the earthquake originated. KARK asked AGS geologist, Scott Ausbrooks, the questions on everyone's mind.
Is their an earthquake trend in Faulkner County?
Geologist Scott Ausbrooks said Faulkner County has settled into a pattern.
"We actually noticed there is a trend. It started back in October. We have big earthquakes, then they tend to go back down and then you have quiet," said Ausbrooks.
Why was this earthquake felt by so many people throughout the state?
Sheer magnitude, said Ausbrooks.
"When you go from a 3 to a 4" said Ausbrooks referring to the Richter scale, "that's 32 times more energy released. This was a 4.7, close to a five, so when you go to 4.7 it's 900 times more energy released in a 5."
Will we see bigger quakes in Faulkner County?
While it's unlikely, Ausbrooks said we could see even bigger quakes from the nearly four mile long fault.
"You could expect, if the whole fault went at one time, the whole fault ruptured, which we haven't seen at this point, you could generate anywhere from a 5.0 to a 5.5."
What's causing the earthquakes?
According to Aubrooks, there are two possible causes to the earthquakes in Faulkner County. One possibility is the region's history of earthquakes. The area experienced the "Enola swarm" in 1982, which produced similar sized earthquakes for three years.
The other possibility is the disposal of fracking fluid into the earth. Fracking fluid is used in the natural gas drilling process. Once the process is complete, that fluid is extracted and disposed of into the earth through what's known as an injection site.
"What we see are these tight clusters [of earthquakes] and what we have not ruled out is the possibility related to injection wells," said Ausbrooks. "Once they're done with that hydro-fracking process, they take that water and dispose of it. And there are cases where injection wells have induced seismicity."
The Arkansas Geological Survey should know by August if those injection sites are to blame.
Did Sunday's earthquake effect the New Madrid fault?
In a word, no.
"It would take a tremendous sized earthquake to have even remotely triggered something there. It's not unheard of, but given the distance, I would not expect anything to happen like that."
Is their an earthquake trend in Faulkner County?
Geologist Scott Ausbrooks said Faulkner County has settled into a pattern.
"We actually noticed there is a trend. It started back in October. We have big earthquakes, then they tend to go back down and then you have quiet," said Ausbrooks.
Why was this earthquake felt by so many people throughout the state?
Sheer magnitude, said Ausbrooks.
"When you go from a 3 to a 4" said Ausbrooks referring to the Richter scale, "that's 32 times more energy released. This was a 4.7, close to a five, so when you go to 4.7 it's 900 times more energy released in a 5."
Will we see bigger quakes in Faulkner County?
While it's unlikely, Ausbrooks said we could see even bigger quakes from the nearly four mile long fault.
"You could expect, if the whole fault went at one time, the whole fault ruptured, which we haven't seen at this point, you could generate anywhere from a 5.0 to a 5.5."
What's causing the earthquakes?
According to Aubrooks, there are two possible causes to the earthquakes in Faulkner County. One possibility is the region's history of earthquakes. The area experienced the "Enola swarm" in 1982, which produced similar sized earthquakes for three years.
The other possibility is the disposal of fracking fluid into the earth. Fracking fluid is used in the natural gas drilling process. Once the process is complete, that fluid is extracted and disposed of into the earth through what's known as an injection site.
"What we see are these tight clusters [of earthquakes] and what we have not ruled out is the possibility related to injection wells," said Ausbrooks. "Once they're done with that hydro-fracking process, they take that water and dispose of it. And there are cases where injection wells have induced seismicity."
The Arkansas Geological Survey should know by August if those injection sites are to blame.
Did Sunday's earthquake effect the New Madrid fault?
In a word, no.
"It would take a tremendous sized earthquake to have even remotely triggered something there. It's not unheard of, but given the distance, I would not expect anything to happen like that."
Comments
I know several people who have called Gov. Beebe's office today only to be told..."We have no authority over this activity. You will have to call tha Arkansas Oil and Gas Comission."
To most people reading this it is just a topic of discussion, but for hundredes of people in the immediate vicinity it could be a matter of saving their property and lives. Maybe the injection wells aren't causing this, but the State geoligist says that there is one well to the immediate north and one to the south. They need to be completely shut down for at least 6 months just to see if it has any effect.
Please call Chesapeak, SWN, The oils and Gas Comission, the gov office.
One of you reporters at KARK needs to take hold of this story. You could be another Geraldo, make a name for yourself and journalistic integrity AND help save lives.
To most people reading this it is just a topic of discussion, but for hundredes of people in the immediate vicinity it could be a matter of saving their property and lives. Maybe the injection wells aren't causing this, but the State geoligist says that there is one well to the immediate north and one to the south. They need to be completely shut down for at least 6 months just to see if it has any effect.
Please call Chesapeak, SWN, The oils and Gas Comission, the gov office.
One of you reporters at KARK needs to take hold of this story. You could be another Geraldo, make a name for yourself and journalistic integrity AND help save lives.
jim S.
March 1, 2011 at 6:59 pm
Maybe you should check your articles before you release them to the public. Anyone with a 5th grade education knows the difference between there, their, and they're. The subhead should read "Is there an earthquake trend in Faulkner County?" The word used by the reporter is their, a possesive pronoun which is the incorrect choice. Totally trashes the credibility of your report. And google has issues with content mills...
Lynda A.
March 1, 2011 at 4:43 am
