ENID, Okla. — Enid and Garfield County Emergency Management has received several reports of damage following two earthquakes Sunday.
Some damage in Enid and Garber involved cracks, Director Mike Honigsberg said Monday.
At least one home in Breckinridge had major brick separation from doors and windows following the first quake, he reported Sunday.
There also were structural issues with sheetrock cracking above doors and windows, and some stairstep cracking in some areas of brick, Honigsberg said.
U.S. Geological Survey reported both quakes, at 5:17 p.m. and 9:40 p.m. Sunday, measured magnitude 4.2. The first was centered near Breckinridge, 10 miles east-northeast of Enid. It was 1 mile deep. The second occurred in the same area, with a depth of 3 miles.
Home owners Jonah and Brandi Davidson, who just moved into the home two weeks ago, have earthquake insurance.
Brandi Davidson was at home, in the kitchen, when the first earthquake suddenly struck.
"It sounded like an explosion," she said.
Everything shook, and items fell off walls, Davidson said.
"I knew it was at our back door. I knew it was close. It rattled our feet on the ground," she said.
It took some time to discover the damage to the home.
"I think we were in shock," Davidson said.
Oklahoma Geological Survey initially recorded lower magnitudes on both quakes, but is deferring to the "moment magnitude" 4.2 reported by USGS, state seismologist Jake Walter said.
"The first event was a little bit larger. Even though it's the same magnitude, the size is a little bit larger," he said.
The depths of both quakes are not yet resolved, Walter said.
"Most Oklahoma earthquakes are generally shallow, if you compare them to, say, earthquakes that occur in California. When an earthquake is shallower, then the potential for damage on structures increases," he said. "These particular earthquakes, right now it's too early to accurately resolve the depths. One of the things that we're working hard at is trying to better resolve those depths.
"We don't necessarily know the depths right now. So, there's just a large degree of uncertainty in the depths."
OGS Director Jeremy Boak said he believed recent earthquakes in the area south of Enid, near Kingfisher and Canadian counties, were the subject of a recent directive from Oklahoma Corporation Commission directed at the oil and gas industry.
"Those are more closely related, in space and time, in location and time, to frack jobs. They're smaller, and the industry at least feels they've been able to actually stop them, in some cases, by changing their frack design," he said. "Those are a different brand, and they tend to be shallower."
When Boak first started with OGS, there was talk of the "Enid Gap" — where few earthquakes have been centered — he noted.
"There were fewer earthquakes really in a sort of belt that kind of passed through Enid," Boak said. "That gap has narrowed, I think."
Two smaller quakes also occurred Monday, according to USGS. The first was a magnitude 2.7 that struck at 12:35 a.m. about 9 miles northeast of Enid and 4 miles north-northwest of Breckinridge. It was 2 miles deep. The second was a magnitude 2.6 that struck at 6:16 a.m. about about 9 miles northeast of Enid and 3 miles north-northwest of Breckinridge. It was 3 miles deep.
"Right now we're in the process of studying that area," OCC spokesman Matt Skinner said. "There are a number of Arbuckle disposal wells in the area, but there's a number that are inactive. There are four active Arbuckle disposal wells within the immediate area. Right now, our induced seismicity team is going through the data and taking a look at their operations."
USGS records show the two Sunday quakes are the largest temblors recorded this year in Oklahoma, and only the third measuring magnitude 4.0 or greater. A magnitude 4.0 quake occurred 14 miles east-northeast of Mooreland on Feb. 16. It was the largest quake in Oklahoma since a magnitude 4.3 temblor near Medford in September 2017.
Since the beginning of the year, there have been 26 magnitude 3.0 or greater earthquakes recorded in the state, according to the USGS. Last year, as of March 5, 2017, there had been 43 magnitude 3.0 or greater quakes.