One of the largest earthquakes recorded in Northwest Oklahoma history struck Saturday morning.
A magnitude 5.1 quake — the largest since a magnitude 5.6 temblor occurred near Prague, Oklahoma, in 2011 — was centered at Aline, Oklahoma, located 17 miles northwest of Fairview, Oklahoma and 45 miles west of Enid, Oklahoma, according to the U.S. Geological Survey (USGS). It occurred at 11:07 a.m., and was 1.2 miles deep.
The temblor was followed, at 11:17 a.m., by a magnitude 3.9 quake at Waynoka, Oklahoma, located 18 miles northwest of Fairview, Oklahoma and 45 miles west of Enid, Oklahoma. It was 3.1 miles deep.
A magnitude 3.5 temblor was recorded at 12:21 p.m. at Cleo Springs, Oklahoma, located 17 miles north-northwest of Fairview, Oklahoma and 39 miles west of Enid, Oklahoma. It was 8 miles deep.
A smaller quake, measuring magnitude 2.5, was recorded at 11:41 a.m. at Waynoka, Oklahoma, located 19 miles northwest of Fairview, Oklahoma. It was 3.1 miles deep.
"There likely will (be) continuing aftershocks for several days, and possibly weeks. The aftershocks should be smaller in magnitude, but we can't rule out the possibility of a larger earthquake," USGS Earthquake Hazards Program Central & Eastern U.S. Coordinator Robert Williams said Saturday.
He said the 2011 earthquake near Prague released about five times the energy as Saturday's temblor.
Neither the Major County nor the Alfalfa County sheriff's offices in the state had received reports of damage.
"As far as I know right now, no major damage," Alfalfa County Emergency Management Director Dianne Phillips said. "We'll still get basic reports. I know oil companies are out checking their pipelines ... and people are still out, and away, for the day. But, so far, no major damage. No major damage in this area.
"It's just the same thing, we're going to have cracks between the walls and the ceiling just getting bigger. But as far as any major (damage), I have not had any reports yet."
She said some items fell off shelves, and cabinet doors came open.
No injuries have been reported either, officials say.
"Not quite the big one, but pretty damn close to it," Dave Altman, of Fairview, Oklahoma, posted on Facebook.
Oklahoma Corporation Commission spokesman Matt Skinner said the regulatory agency started notifying wastewater injection well operators on Thursday of a plan of action for the region.
"We are going to announce it publicly Tuesday," he said. "It will cover about 5,000 square miles, and it definitely includes Fairview."
The location of Saturday's earthquakes is not exact, Skinner noted.
"It will take the Oklahoma Geological Survey some time to do what we call a corrected hypocenter. The computer readings are sometimes pretty close, but the initial USGS stuff, that's just where the computer is guessing it is," he said. "Then OGS takes that, and works it by hand and figures out a much more accurate location."
He said the margin of error is sometimes rather large, in terms of location.
"We won't know for sure exactly where it was located with any more precision until OGS reports it to us," Skinner said.
Initially, the OGS reported the big quake as a magnitude 4.6 before later upgrading it to a 4.8.
The plan of action will involve a large-scale volume reduction, he said.
"We will be releasing all the details on Tuesday," Skinner said. "It involves hundreds of disposal wells."
Volume reductions will be done in stages, he said.
"That's because of researchers, the warning from researchers that you don't want any sudden change in pressure. You need to phase these in. And that's what we've done in all of our past actions, that's what Kansas did in their action. They're all phase-ins," Skinner said.
When the OCC took action in Fairview recently, all the data showed regional action would need to be taken, he said.
"As we said then, at that time, we have to take a larger approach. We've been working on this for some time, before the large-scale quakes in Fairview, we've been working on this plan," Skinner said.
The quake was felt throughout Oklahoma and neighboring states.
In southwest Enid, one reader said the quake felt like someone hit their home with a truck.
Readers reported feeling the lengthy temblor in the Oklahoma cities of Woodward, Stillwater, Dover, Lacey, Muskogee and Tulsa.
The initial USGS report of 5.1 marks the biggest earthquake ever recorded in Northwest Oklahoma. The area is about 100 miles northwest of Oklahoma City.
"This morning's earthquake is likely the third largest earthquake in Oklahoma state history," Williams said.
The strongest earthquake on record in Oklahoma is a magnitude 5.6 centered in Prague in November 2011 that damaged 200 buildings. A magnitude 5.5 was recorded in El Reno in 1952.
As of 1 p.m. Saturday, there had been 3,206 responses on the "Did You Feel It" site offered by the USGS, he said.
"We encourage Oklahoman's that felt this earthquake to help USGS understand the ground shaking by giving your report to the DYFI site," Williams said.
"Oklahomans living in the north-central part of the state should be prepared for earthquakes," he said.
For more information on preparation, visit http://earthquakes.ok.gov/earthquake-preparedness.
Miller writes for the Enid, Oklahoma News.