Earthquake with 4.0 Magnitude Hits Oklahoma

Staff and Wire Reports

JONES, Oklahoma -- A 4.0 magnitude earthquake was recorded near Jones in central Oklahoma Friday. The quake is just one of close to two dozen earthquakes felt in the past year in Oklahoma.

The U.S. Geological Survey recorded the quake at 9:18 a.m. Friday about 17 miles northeast of Oklahoma City. A second earthquake was recorded at 9:27 a.m. about 16 northeast of Oklahoma City and one mile northeast of Jones with a 3.8 magnitude.

Seismologist Austin Holland of the Oklahoma Geological Survey said the quake was felt in Midwest City, Jones and surrounding areas.

"It is very unusual," he said. "Earthquakes of these sizes don't need big faults. They can occur on very small fractures in the earth."

Holland said the increase of seismic activity in Oklahoma is known as an earthquake swarm.

"An earthquake swarm usually consists of hundreds to thousands of earthquakes. Some are felt some are not felt. They're occurring on small fractures or faults," Holland said.

Experts said while earthquake swarms are not damaging, researchers are studying what started them.

"We can't speak to the actual cause but we're putting more instruments out with more locations, and more instrumentation we should be able to more precisely locate the earthquakes," Holland said.

Ryan Dragg said he was jolted by the quake where he works on the ninth floor of the VA Medical Center in Oklahoma City. He said he and a co-worker briefly left the building.

"We got jolted up here. We looked at each other and said, let's go outside," Dragg said. "I don't know proper protocol for earthquakes in Oklahoma."

After a series of earthquakes rattled North Texas last summer, preliminary research shifted the focus to a Chesapeake re-injection well located near a major fault line that runs under the airport. There is no proven scientific study that the wells caused the quakes, but Chesapeake shut down both wells as a precaution. SMU's Seismology Professor Brian Stump said the study is ongoing and still preliminary.

"While initial studies show a possible correlation between the earthquakes and one re-injection well used to dispose of waste fluids, it would be premature to state unequivocally that salt water disposal at this well is responsible for the earthquakes," Stump said back in August 2009.

Oklahoma Corporation Commission Matt Skinner said there is currently active drilling in Oklahoma county.

"Currently in Oklahoma County, we have two active drilling rigs. In fact one of those may now have shut down," Skinner said.

But the cause of all the recent earthquakes will all come down to science and more studies.

"There's no reason to think that these are currently being caused by manmade activities, manmade drilling or anything like that. I can say confidently that it's an earthquake swarm. Thousands of earthquakes occur every day of this size, of this magnitude 3 range so it's not that unusual," Holland said.

The quake is at least the third in the area since Sunday. A 2.8 quake was recorded at 11:16 p.m. Sunday and a 3.3 quake was recorded at 4:05 a.m. Thursday.

Holland said residents will probably feel more earthquakes in the next few days or weeks, but no damaging earthquakes are expected in the future.

Quakes of magnitude 2.5 to 3 are generally the smallest felt by people.

Callers into NEWS 9 from Midwest City, Del City, Choctaw and Spencer reported that they felt shaking that they would associate with earthquakes.

Some minor damage was reported including cracked chimneys.

No injuries were reported.

Report feeling the earthquake