By JUDY SHERIDAN
The series of recent earthquakes in northern Parker County could have been a domino effect triggered by a single injection well, according to John Wickham, Ph.D., a professor in the Department of Earth and Environmental Sciences at UTA.
“Once the stress is released on one small fault, it moves a bit and pushes the rocks that are on the end of the fault and increases the stress there. That can trigger another earthquake,” he said. “I’m not familiar with the area; I’m just saying what’s possible.”
The earthquakes — seven between Nov. 5 and Nov. 8 — have been recorded west of Briar, south and east of Springtown, in the Reno area — with an aftershock in Newark — and near Azle, with magnitudes ranging from 2.4 to 3.0.
While natural causes cannot be ruled out because stress is always building up in the earth’s crust, it is more likely that an injection well — used to dispose of fracking waste — is to blame, Wickham said.
“The research indicates that earthquakes are not caused by fracking,” he said, “but they could be linked to the injection wells that go a lot deeper, 10,000 feet or more.
“It’s well known that when you put fluids under pressure in a rock formation, it can release natural stress buildup.”
It is improbable, but possible, Wickham said, that the small quakes will lead to larger ones.
“Sometimes that does happen,” he said, “but we’re not near the tectonic plate boundaries in Texas. The larger earthquake action takes place along the plate boundaries in California, Japan, the coast of Chile. The largest recorded in Texas is a 5.0. The largest ever recorded is on the order of 9.”
The scale is not linear in terms of the amount of energy released, Wickham said, but logarithmic.
“The difference between a 1 and 2 is a factor of 30,” he said, “the difference between a 4 and 5 is a factor of 900.”
Ed Ireland, executive director of the Barnett Shale Energy Education Council, believes, like Wickham, that earthquakes were not caused by the actual drilling for natural gas.
“The level of drilling is low,” he said, “There are only 35 rigs in all of the Barnett Shale, compared with 200 in 2008.”
Ireland said scientists have observed seismic activity around disposal wells but have not proven whether it’s a random correlation or a real connection.
“My understanding is that three things have to be present if there is induced seismic activity,” he said, “There has to be a fault — and there are faults in Parker County — the fault has to be under pressure already, and the disposal well has to be injected at such a pressure that it relieves the strain on a fault.
“In some cases, where there is a question, operators reduce the injection pressure.”
Ireland said Cliff Frohlich, associate director and senior research scientist at the University of Texas Institute for Geophysics, is the expert when it comes to earthquakes and injection wells.
Frohlich, who studied two years of seismographic data collected on the Barnett Shale — from 2009-11 — thinks the data “suggests that injection-triggered earthquakes are more common than is generally recognized.”
He authored an article entitled “Two-year survey comparing earthquake activity and injection-well locations in the Barnett Shale, Texas,” published in 2012 in the Proceedings of the National Academy of Sciences of the United States of America.
In the article Frohlich hypothesizes that “injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented nearby fault that is experiencing regional tectonic stress.”
His study uncovered 67 earthquakes — eight times as many as have been reported — with magnitudes 1.5 and larger, with “all 24 of the most reliably located epicenters — the spot on the surface above an earthquake’s point of origin — occurring in eight groups within 3.2 km of one or more injection wells.”
In Johnson County, however — although nine of the 27 injection wells were near earthquakes — “elsewhere no earthquakes occurred near wells with similar injection rates.”
By JUDY SHERIDAN
- Aledo ExtrA
SPRINGTOWN – After finding that a breaker manufactured by a company with a history of issues contributed to a house fire Friday, Parker County Fire Marshal Shawn Scott is urging Parker County residents with Federal Pacific Electric Stab-Lok circuit breakers to call an electrician and get them checked for safety.
Candidates have filed for city, school board elections
Filings for May 10 city and school board elections are now complete. A summary follows:
On the Aledo ISD school board incumbents David Davis, in Place 6, and Hoyt Harris, in Place 7, have both filed for re-election, each drawing one or more opponents. Farida Goderya has filed for Place 6, opposite Davis, and Riley Morrison and Debra Rogers have filed for Place 7, opposite Harris.
East Parker County Calendar of Events
The East Parker County Chamber of Commerce will welcome retired USAF SMSGT Vernon M. Anderson, Jr., senior technical instructor, Bell Helicopter, Integrated Operations Engineering Support Technical Training Department, as the key note speaker for the March 12 luncheon.
The Sunny Side
WILLOW PARK – Peppered with anecdotes from his stellar baseball career, former Texas Rangers catcher Jim Sundberg gave witness to his Christian faith and told how it changed his life before a crowd of about 200 at the recent annual Trinity Christian Academy dinner and fundraiser.
Aledo ISD approves suicide prevention program
The Aledo School Board approved the LifeLines Suicide Prevention Program in February, lining up with a recommendation from the Student Health Advisory Council, which has spent a year reviewing choices.
Aledo ISD could save up to $2 million
Expecting to save close to $2 million, Aledo ISD trustees recently voted to let district staff pull the trigger on a bank-qualified refunding of some of the district’s outstanding bonds once market conditions are optimum.
Don't feed the deer!
HUDSON OAKS — The city council recently passed an ordinance banning the feeding of deer.
Parker County Sheriff's Report Feb. 27-March 2
Burglary of a vehicle
Deputies were dispatched to the 300 block of James Street in Aledo shortly after 6 p.m. regarding the burglary of a vehicle.
ASK A MASTER GARDENER: Is it too early to start a vegetable garden?
Considering our winter temperatures this year, that’s a good question. When it comes to a successful vegetable garden, timing is everything. The goal in Texas is to have most of your vegetable crops mature before the temperatures soar in mid-summer.
EXTENSION NEWS: Getting more zzzs could help you lose some lbs.
We spend about one-third of our lifetime sleeping. Sleep is important for learning and memory. Sleep also helps our immune system to resist illness and disease, increases response times in emergencies, improves our mood and feelings of wellness and gives us the energy we need to be more active and alert.
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