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
EXTENSION NEWS: Take a mind vacation
For many of us, every day has some sort of stress associated with it. Whether it is something at home or at work, it seems like there are a million things stressing us out and making us feel overwhelmed.
VETERANS’ CORNER: Veterans’ needs the target of recent discussions
Ministers responsible for Veterans Affairs and officials from Australia, Canada, New Zealand, the United Kingdom and the United States completed a series of meetings April 8-11 at the United States Military Academy at West Point, N.Y., discussing the latest research, best practices and various areas of collaboration to address the growing needs of veterans.
ASK A MASTER GARDENER: Blooming natives add color to Texas landscapes
Here are this week’s gardening questions and answers, provided by Parker County Master Gardeners. To submit a question, send it to email@example.com. For more information about Parker County Master Gardeners, or to become a member, call 817-598-6096 or visit www.pcmg-texas.org.
Canyon West to host Taste of Parker County
Prepare your taste buds, because the sixth annual Taste of Parker County is just a few short weeks away, and this year’s event has moved to a larger location to accommodate even more great eats and treats.
Grand jury indictments for April returned
A Parker County grand jury on Thursday indicted a man accused of breaking into his neighbor’s home and threatening him with a BB gun before engaging in a brief standoff with deputies.
Despite cold, peach crops looking rosy
Parker County peach growers won’t know for sure for a few more days, but as of Wednesday, one day after April temperatures plummeted into the low 30s, they’re predicting a good, even rosy, peach harvest for this year’s Parker County Peach Festival.
Aledo ISD "Shattered Dreams" and parent workshop
Aledo ISD high school students will get a taste of what it’s like to be in a car accident with fatalities Thursday, April 17th, and Friday, April 18th, as they participate in “Shattered Dreams,” a program designed to save lives. A parent workshop about the topics addressed in the program will be held from 7 p.m. to 9 p.m. Wednesday, April 17.
Hitting the trail for MS
STEPHENVILLE – The Cowboy Capital MS Trail Ride is a fun-filled event dedicated to raising funds that support national research into the cause and cure for Multiple Sclerosis as well as provide programs to more than 9,000 people in the Lone Star Chapter area whose lives are touched by MS.
Parker County man killed in single-vehicle wreck
A 60-year-old Parker County man was killed around 9:30 a.m. Tuesday in a one-vehicle crash in the 2100 block of FM Road 3325, also known as Farmer Road.
Aledo City Council Place 4 candidates for May 10 election
Early voting for the May 10 general election begins April 28. Following is some information gathered from the candidates for the Place 4 Aledo City Council seat. Aledo Mayor Kit Marshall is running for re-election unopposed.
- More Aledo ExtrA Headlines
- EXTENSION NEWS: Take a mind vacation