Experts say Oklahoma earthquakes will continue even though injection wells are shutting down
NORMAN, Okla. – Don’t expect the shaking to stop anytime soon.
Earthquake experts expect the state to keep rattling, perhaps for years to come, even as the state steps up its search for a solution.
“Increasingly I think we’ll see the earthquake intensity waning, fewer and fewer of the smaller earthquakes we’ve been seeing and probably stretching out longer and longer intervals between anything that’s really large and potentially damaging,” said Oklahoma Geologist Jeremy Boak.
Less than a week after the strongest earthquake in Oklahoma’s modern history, scientists and researchers from around the country are discussing solutions in Norman.
The Oklahoma Geological Survey planned its Seismicity Workshop months ago, but the timing of Saturday’s 5.8 magnitude quake in Pawnee, “probably will flavor the discussion here,” Boak said.
However, experts say it can’t be immediately and definitively attributed to wastewater injection.
Media was not allowed inside the conference room, but an agenda shows several presentations centered around one of Oklahoma’s newest and most-talked-about issues: the relationship between wastewater injection wells and a record number of earthquakes.
“You have to say if the rise was due to injection changes, so is the decline,” Boak told NewsChannel 4. “And we’ve seen about a one-third decline in frequency of earthquakes above magnitude 2.8. So if you believe the increase was due to oil and gas activity, you have to believe the decline is due to decreasing oil and gas activity.”
Hydrofracking is rarely the culprit, Boak said. Instead it’s the process of taking the wastewater that comes up with oil and gas and injecting it back in the ground that can cause the earth to rumble.
“We essentially ramped up so much we began to induce seismicity in the area, and that’s what’s really causing this,” he said.
The Oklahoma Corporation Commission has recently ordered companies to cap their injection wells in hopes of calming the seismic activity. While scientists say it has had a positive impact, the action won’t stop earthquakes altogether.
“Closing down wells doesn’t mean the seismicity will shut off,” said U.S. Geological Survey Geophysicist Daniel McNamara, citing a site in Denver that shifted for decades, even after injection activities were halted. “Even if all wells were to shut off today, there would still be energy in the system and earthquakes occurring for some time.”
The USGS can’t forecast where or when an earthquake will occur, but McNamara says more, stronger earthquakes could be on the way, even if they occur less frequently.
Oklahoma’s faults are capable of producing magnitude 6.0 and greater earthquakes, McNamara said, and he wouldn’t be surprised to see one. In fact, McNamara said he’s surprised Pawnee hasn’t seen stronger aftershocks.
The State Geologist wants people to be prepared for future damage from a stronger quake.
“I think you can’t rule it out,” Boak said. “We’re lucky (the Pawnee earthquake) was in a remote area. There is some damage, and you know that’s unfortunate, but it could have been substantially worse if a larger earthquake like this had happened closer to Oklahoma City, Edmond, places like that.”
Oil companies in attendance, meanwhile, were encouraged to share their private data, in hopes of working toward a long-term solution.
“This is science and science is what it is,” said Kim Hatfield, who leads a seismicity work group for the Oklahoma Independent Petroleum Association. “This is not something we’re doing with a gun to our head. We’re trying to find answers.”
The economics can hurt. Many companies are taking big losses when injection wells close, Hatfield said, as they’re forced to find other places to put their wastewater.
But Hatfield says the industry wants to help the state find solutions.
“It’s certainly give and take and the industry has gone well beyond of what’s been requested. We’re funding a lot of the basic research,” he said. “We want to give them a fuller toolbox so they can approach this in a more measured way and still accomplish the same goals.”