The Edmond Sun

April 1, 2014

Cluster of earthquakes center in Logan County

Mark Schlachtenhaufen
The Edmond Sun

EDMOND — A cluster of magnitude 2.5-3.2 magnitude earthquakes were recorded by seismic instruments Tuesday in Logan County.

Tuesday’s strongest quakes recorded by the Oklahoma Geological Survey and U.S. Geological Survey were:

• Magnitude 3.2 recorded at 7:07 a.m. 4.3 miles south-southwest of Langston;

• Magnitude 3.1 recorded at 1:59 p.m. 2.4 miles southeast of Langston;

• Magnitude 3.0 recorded at 9:07 p.m. 2.4 miles south of Langston;

• Magnitude 3.0 recorded at 3:50 p.m. 2.4 miles south of Langston;

• Magnitude 2.9 recorded at 1:45 p.m. 2.4 miles south of Langston;

• Magnitude 2.8 recorded at 2:26 p.m. 2.4 miles south of Langston;

• Magnitude 2.6 recorded at 3:41 a.m. 3.1 miles south of Langston; and

• Magnitude 2.5 recorded at 10:04 a.m. 8.6 miles north-northeast of Crescent.

The activity comes on the heels of numerous weekend earthquakes which included four magnitude 3.5 quakes, one magnitude 3.6 quake and two magnitude 4.3 quakes Sunday in the Crescent area. Shaking was felt as far away as Tulsa and in Kansas.

“That’s pretty unusual,” said Austin Holland, a seismologist with the Oklahoma Geological Survey. “It caught our attention that there were so many events in the area.”

Holland said a seismometer, an instrument that measures motions including seismic waves produced by earthquakes, has been placed in the area to gather data that could shed light on the cause. Holland said the inquiry includes requesting still-awaited drilling related information from the Oklahoma Corporation Commission.



THE NEMAHA FAULT

The quakes in the Crescent area occurred in the vicinity of the Nemaha fault, Holland said.

The structure, also known as the Nemaha Shale Shaker and the Nemaha Uplift Province, is a 450-mile-long north-south paleostructural feature extending from southeast Nebraska to south-central Oklahoma, according to the USGS. Petroleum exploration began there before 1900 and gas was discovered in Cowley County, Kansas, as early as 1902.

Among the largest fields in the province are the Oklahoma City field in Cleveland and Oklahoma counties and the Lovell-Crescent field in Kingfisher and Logan counties, according to the USGS.

Last month, the Oklahoma Geological Survey, a state agency for research and public service charged with investigating the state’s land, water, mineral and energy resources, released a position statement on the Prague earthquake sequence of 2011.

The authors stated the OGS has been working with the Oklahoma Corporation Commission to analyze data related to the 2011 Prague sequence, which included a main shock of magnitude 5.7, the strongest recorded quake in the state since 1952.

The interpretation that best fits current data is the Prague earthquake sequence was the result of natural causes, the authors stated. Further studies of seismic activity, which includes recent activity in the Arcadia Lake area, will result in a better understanding of seismicity statewide, Holland said.



marks@edmondsun.com | 341-2121, ext. 108