North Texas Earthquakes Continue, But Too Small To Feel

Aug 25, 2014

In January a series of earthquakes rocked the small North Texas towns of Azle and Reno. Many blamed the events on high-pressure injection wells used to dispose fluids from ‘fracking.’ Researchers are still studying what caused the earthquakes, but the state’s oil and gas regulator is seeking greater authority to suspend injections.

The Texas Railroad Commission is the agency that regulates oil and gas in the state. For years the agency claimed there was no connection between high-pressure injection wells and earthquakes, but they’ve started to look into it. The Railroad Commission has hired a seismologist, Dr. Craig Pearson. Testifying before the Texas House subcommittee on seismic activity, Peterson explained one possible cause of the quakes.

"When you start injecting into an underground reservoir you begin to build the pressure anomaly within that reservoir," Peterson said at a hearing for the Texas House Subcommittee on Seismic Activity. "We believe that it’s that change in pressure that’s affecting existing faults in the earth and allowing them to move and cause earthquakes."

Peterson also reported that there haven’t been any “felt” earthquakes in Azle and Reno since January of this year. But a research team from Southern Methodist University has recorded a lot of micro-seismic events, that is, earthquakes with less than a 3.0 magnitude on the Richter scale.

Last week, the Texas Railroad Commission proposed new rules to regulate high-pressure injection wells. The rules included new reporting requirements for disposal wells and more authority for the agency to suspend, or outright terminate wells.

"We’re going to look at those disposal wells in the vicinity of that epicenter and probably suspend their operations until as an emergency response," Peterson said.

A research team from Southern Methodist University is studying the cause of the quakes. Their findings should be published by the end of the year.