Tremors recorded in Texas shale

Dec. 19 (UPI) -- A cluster of seismic activity occurred Monday in western Texas in parts of the Permian shale basin, the U.S. Geological Survey reported.

USGS showed three small tremors just south of the Texas border with New Mexico, the largest of which was a magnitude-3 quake with an epicenter some 35 miles south of New Mexico's border.

That follows a magnitude-5.4 quake Friday in Midland, Texas, about 100 miles east of Monday's tremors.

Seismic activity is a concern in U.S. shale reserves. In Oklahoma, home to the Anadarko shale basin, seismicity peaked in 2015, with more than 900 tremors of greater than magnitude 3 recorded.

Water injections into shale beds can increase the potential for earthquakes. Oklahoma legislatures had imposed limits on the volume of water injected as part of an effort to reduce tremors that are ostensibly tied to drilling.

In response to last week's magnitude-5.4 quake, the Texas Railroad Commission, the state's energy regulator, sent its response team to the area to "take any necessary actions to protect public safety and the environment."

RRC said it called on operators last December to stop injecting waste water in the Midland seismic response area.

"Staff will review permit requirements for other injection wells in the area as it prepares for a response to reduce the frequency and intensity of earthquakes," the commission said in a statement emailed to UPI.

Texas is home to the largest inland shale oil basins in the country. Total U.S. crude oil production is forecast to reach 12 million barrels per day or so on average next year and the state's Permian basin alone is churning out around 5 million bpd.

More than 200 earthquakes of magnitude 3 and greater shook Texas in 2021, more than double the 98 recorded in 2020.