5.1M Quake Among Latest Swarm of Temblors in Oklahoma

A 5.1 magnitude earthquake shook northwest Oklahoma and was felt in seven other states on Feb. 13, the U.S. Geological Survey said, the third-strongest temblor ever recorded in the state where the power and frequency of earthquakes has dramatically increased in recent years.

The earthquake centered about 17 miles north of Fairview in northwestern Oklahoma occurred at 11:07 a.m. and was reportedly felt across Arkansas, Iowa, Kansas, Missouri, Nebraska, New Mexico and Texas, the USGS said. At least 10 smaller quakes ranging in magnitude from 2.5 to 3.9 were recorded in the same area by late afternoon, according to the USGS. A magnitude 3.1 quake occurred near Crescent, about 75 miles east of Fairview, the USGS said.

Oklahoma’s stronger and more frequent earthquakes have been linked to the injection into the ground of the briny wastewater left over from oil and gas production. The latest10 earthquakes were in the same lightly populated area near Fairview, a town of about 2,600 that’s about 100 miles northwest of Oklahoma City. The area has had several quakes of magnitude 4.0 since the start of the year.

Geologists say earthquakes of magnitude 2.5 to 3.0 are generally the smallest that are felt by humans, and damage is not likely in quakes below magnitude 4.0.

Fairview police and the Major County Sheriff’s Office had no reports of injury or significant damage. Sheriff’s dispatcher Cheryl Landes said there had been several calls from concerned residents, but no damage more than pictures knocked off shelves and walls.

The strongest earthquake on record in Oklahoma is a magnitude 5.6 temblor, which has also been linked to wastewater injection. It was centered in Prague, about 55 miles east of Oklahoma City, in November 2011 and damaged 200 buildings and shook a college football stadium in Stillwater, about 65 miles away. The second-strongest was a 5.5 magnitude earthquake in April 1952 that was centered in El Reno, on the western edge of Oklahoma City.

The hundreds of recent quakes have been mostly small to medium sized, and have caused limited damage. But a quake did knock out power in parts of an Oklahoma City suburb several weeks ago, and last month about 200 unhappy residents packed a forum at the state capitol convened by critics of the state’s response.

Regulators have recommended reducing the volume or shutting down some of the disposal wells. Gov. Mary Fallin in January approved the use of nearly $1.4 million in state emergency funds for state agencies working to reduce the number of earthquakes linked to the wastewater disposal.

Oil and gas operators in Oklahoma, where the industry is a major economic and political force, have resisted cutting back on their injections of wastewater.

The Oklahoma Corporation Commission, which oversees the oil and gas industries in the state, said that it has completed the major work on a regional plan to address earthquakes in western Oklahoma.

“The plan will involve a large-scale regional reduction in oil and gas wastewater disposal for an approximately 5,000 square mile area in western Oklahoma,” spokesman Matt Skinner said. He said the complete plan will be released today.