State has unfamiliar threat: Earthquakes
The West Texas earth shook one day in November, shuddering through the two-story City Hall in downtown Pecos, swaying the ceiling fans at an old railroad station, rattling the walls at a popular taqueria.
The tremor registered as a 5.4 magnitude earthquake, among the largest recorded in the state. Then, a month later, another of similar magnitude struck not far away, near Odessa and Midland, twin oil country cities with relatively tall office buildings, some of them visible for miles around.
The earthquakes, arriving in close succession, were the latest in what has been several years of surging seismic activity in Texas, a state known for many types of natural disasters but not typically, until now, for major earth movements. In 2022, the state recorded more than 220 earthquakes of 3.0 magnitude or higher, up from 26 recorded in 2017, when the Bureau of Economic Geology at the University of Texas began close monitoring.
So unheard-of were strong earthquakes in the flat, oil-rich expanse about a six-hour drive west of Austin that some residents at first mistook the November quake for a powerful gust of wind. Lloyd Chappell, a retired propane deliveryperson who was in his recliner at the time, thought one of his grown sons was making a joke of shaking his chair. But no one was there. His water sloshed around in his glass for 30 long seconds.
“We've heard noises before — out there in the oil field, they drop big tanks, or things like that,” said Chappell, 66. “But I'd never felt that before.”
The vast majority of the temblors have been concentrated in the highly productive oil fields of the Permian Basin, particularly those in Reeves County, north and west of the city of Pecos. The county's official population of 14,000 does not account for thousands of mostly male transient workers staying in austere “man camps” and RV parks, brought there by the promise of good pay in exchange for long hours, stark terrain and dangerous work.
Now earthquakes have become part of the same calculation.
“In West Texas, you love the smell of the oil and gas patch because it's the smell of money,” said Rod Ponton, a former Pecos city attorney who once unintentionally attained international fame by appearing as a worried cat during a court hearing on Zoom. “If you have to have the ground shaking every two or three months to make sure you have a good paycheck coming in every month, you're not going to think twice about it.”
The economy of Pecos and a handful of surrounding towns — some little more than sand-blown highway intersections and crowded gas station convenience stores — revolves around the oil fields.
In Reeves County, oil and gas production has increasingly meant hydraulic fracturing, a process of extraction that produces, as a byproduct, a huge amount of wastewater. Some of that wastewater is reused in fracking operations, but most of it is injected back under the ground. It is that process of forcing tens of billions of gallons of water into the earth that, regulators and geoscientists agree, is to blame for many of the earthquakes.
The connection between wastewater disposal and earthquakes has been long understood. Other states with substantial fracking operations have also seen the ground shake as a result, including Oklahoma, where a similarly rapid increase in earthquakes more than a decade ago included a 5.6 magnitude quake in 2016 that forced the shutdown of several wastewater wells.
Getting rid of the “produced” water is an important business in West Texas, and locations labeled “SWD” — for saltwater disposal — dot the landscape of drilling rigs and truckworn roads. Each of the past few years, about 168 billion gallons of wastewater have been disposed of in this way, according to data from the Railroad Commission of Texas, which regulates the oil industry.
Texas only recently began its statewide program of monitoring for earthquakes, after a series of small quakes in North Texas rattled residents of Dallas and Fort Worth. The monitoring started in 2017 — just as petroleum development accelerated in the Permian Basin, particularly in and around Reeves County — and began to detect the increasing seismic activity.
“It was really very fortuitous,” said Peter Hennings, the principal investigator for the Center for Integrated Seismicity Research at the University of Texas.
Hennings said that while natural earthquakes can occur in West Texas, they can also be induced through human activity: the injection of a large amount of water in a short period of time adds fluid pressure under the earth, which essentially decreases the “clamping” between rocks along natural faults and allows them to slip, creating an earthquake.
And seismologists have established a relationship between smaller earthquakes and larger ones, Hennings said: The more small earthquakes you have, the greater the likelihood of a bigger one.
The problem can be addressed by cutting back on the amount of saltwater being injected back into the ground. Oklahoma, for example, did so in recent years and has seen a reduction in the number of earthquakes.
In 2021, the Texas Railroad Commission noted “an unprecedented frequency of significant earthquakes” in and around Reeves County and asked companies to implement their own wastewater plans, hoping to decrease the number of 3.5 magnitude or greater earthquakes by the end of this year.
To address earthquakes outside Odessa and Midland, state regulators suspended permits for deep disposal wells. And just north of the border with Texas, New Mexico regulators have been taking their own steps to control saltwater disposal, including $2 million in fines to Exxon over compliance failures.
The fracking issue has been a big one for Texas environmental groups, which have raised concerns about pollution, climate change, social inequity — and now earthquakes. “It is past time for the Railroad Commission of Texas to update the rules on injection wells,” said Cyrus Reed, the conservation director for the Sierra Club's Lone Star Chapter, adding that there should be limits on injecting “polluted fracking wastewater” in places impacted by seismic activity.
“In West Texas, you love the smell of the oil and gas patch because it's the smell of money. If you have to have the ground shaking every two or three months to make sure you have a good paycheck coming in every month, you're not going to think twice about it.”
— Rod Ponton, former Pecos, Texas, city attorney