Amid New Earthquakes, Researchers Head to Irving

Updated, 8:31 a.m., Jan. 7: 

The U.S. Geological Survey confirmed five additional small earthquakes late Tuesday and early Wednesday in Irving. The largest hit with a magnitude of 3.1. That brings the city's trembler total to 28 since last September. 

Original story, Jan. 6:

Editor's note: This story has been updated from a version that was originally published at KUT.org.

A team of seismologists headed to the North Texas town of Irving on Monday. Like some other Texas towns, Irving has experienced scores of small earthquakes lately, 23 since last September, and the city is hoping to figure out what’s behind the shaking.

The latest four earthquakes, all on Tuesday, carried magnitudes of 3.5,  3.6, 2.9 and 2.7, according to the U.S. Geological Survey – powerful enough to be felt in Fort Worth and Dallas. 

The upsurge in quakes started in Texas around the time the oil and gas boom took hold several years ago. Residents in many parts of the state blame them on wastewater disposal wells, where fluid byproducts of oil and gas drilling are pumped deep into the ground. Scientists have shown how injecting fluid into the ground can cause earthquakes.

After a spate of quakes in the North Texas town of Azle, the Railroad Commission of Texas, the state’s oil and gas regulator, hired a seismologist, David Craig Pearson, and passed new regulations for disposal wells. The commission says it is not investigating the Irving quakes.

“The Railroad Commission is not investigating seismic activity around Irving,” Ramona Nye, a spokeswoman for the commission, wrote in an email to StateImpact Texas. “Specifically, there are no disposal wells in Dallas County, and there is only one natural gas well in the vicinity, and it is an inactive well.”

Nye added: “The Railroad Commission is aware of these recent earthquakes in the Irving area, and Dr. Pearson has put [Southern Methodist University] researchers in contact with city of Carrollton personnel so that SMU researchers can install a seismometer in the area to further pinpoint the locations of these seismic events." 

Scott Hudson, the Carrollton environmental services director, said that to his knowledge, no one from that city had been in touch with the Railroad Commission. But Chris Hillman, the Irving city manager, said his city had “reached out” to the commission and that SMU researchers were traveling to Irving to install the monitor.

“As we learn and understand more about these issues, we’ll continue to pass along more information to our residents,” Hillman said.

Nye said Pearson was not available for an interview.

In a statement emailed to StateImpact Texas, Brian Stump, SMU’s chair in geological sciences, said installing the monitor will help researchers understand what’s happening under Irving.

“Pinpointing the exact location of the earthquakes is dependent on local seismometers and thus the first step in understanding the nature of the seismic activity,” Stump wrote. “The team will continue to interact with local officials about the seismic events.”

Irving's latest earthquakes weren't the only ones to shake Texas on Tuesday. A 3.5-magnitude tremor also struck outside the West Texas town of Snyder, according to the U.S. Geological Survey. The sparsely populated area has also felt a surge of quakes in recent months. 

Tribune reporter Jim Malewitz contributed to this report.