AZLE — Residents in Azle in northwest Tarrant County say enough is enough after yet another mild earthquake on Tuesday morning.
The U.S. Geological Survey recorded a 3.0-magnitude tremor at 8:24 a.m. That follows minor quakes very early Saturday morning and again Monday morning.
Last Tuesday, the earth twitched three times.
University of Texas earthquake researcher Cliff Frolich said waste water injection wells from fracking could be responsible.
"I'd say it certainly looks very possible that the earthquakes are related to injection wells," he said in an interview from Austin.
Frolich notes, however, that thousands of such wells have operated in Texas for decades, with no quakes anywhere near them. He adds that there are probably a thousand unknown faults beneath Texas.
Azle mayor Alan Brundrett says it's important to determine whether this latest series of quakes are man-made.
"What could it cause, down the road?" he asked. "What if a 5.0 happens and people's houses start falling in on them?"
Brundrett has installed an earthquake alert app on his smartphone. It shows a dozen minor quakes near his town since November 5.
"Enough is enough!" said Keith Krayer, a resident of Briar, just north of Azle. "My wife, she's having panic attacks because of it."
Krayer has been spending time in the Azle library looking for answers into the mystery tremors.
A study on a 2009 earthquake cluster near Cleburne concluded: "The possibility exists that earthquakes may be related to fluid injection."
That study was authored by several researchers, including geologist Cliff Frolich.