By Kevin Simpson
The Denver Post

Wastewater injections from oil and gas operations likely has led to the recent sharp increase in earthquakes across central Oklahoma, according to researchers, including two from the University of Colorado Boulder.

The study, which appears in the journal Science, used advanced hydrogeological models to gauge how pressure from wastewater injected into underground rock seeped into faults where seismic activity occurred.

Oklahoma averaged about two 3.0-magnitude or higher quakes per year before 2008. Up to May 2 of this year, the U.S. Geological Survey recorded 145. That spike comes amid the state’s boom in hydraulic fracturing — or “fracking,” a method for extracting oil and gas that produces high volumes of wastewater.

Experts have drawn the distinction that while it’s not the fracking itself that may trigger quakes, the pressurized disposal of the waste fluid underground has raised concerns.

More: Spike in Oklahoma Quakes Likely Caused by Injection Wells, Study Says - the Denver Post

The close flyby of Earth by asteroid 2012 DA14 on Friday (Feb. 15) could trigger a quake on the space rock, scientists say.

“We are going to be looking closely for evidence of seismic activity on 2014 DA14 as it passes by,” Richard Binzel, a professor of planetary science at MIT, said in a statement. “This is the first case of an object coming close enough to experience quakes and where we have enough notice to plan observations.”

During the unprecedented close approach, 2012 DA14, which is about half the size of a football field, will cruise within 17,200 miles (27,700 kilometers) of the planet. It poses no threat to Earth, but the flyby marks the first time scientists like Binzel have had the chance to observe such a big space rock this close-up.

More: Friday Flyby May Trigger ‘Asteroid-Quake’ on Space Rock

North Korea appeared to have conducted its third underground nuclear bomb test Tuesday, as the U.S. Geological Survey reported a seismic disturbance centered near the site of the secretive regime’s two previous nuclear tests.

The area around the reported epicenter of the magnitude 4.9 disturbance has little or no history of earthquakes or natural seismic hazards, according to U.S. Geological Survey maps. The disturbance took place at a depth of about 1 kilometer, the USGS said.

There were no initial reports concerning the activity on the North’s state-run Korean Central News Agency on Tuesday.

“It’s a nuclear test,” said Jeffrey Lewis, director of the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies at the Monterey Institute of International Studies. “That magnitude and that location — it’s awfully unlikely it’s anything else.”

More: Seismic Activity Reported in Area of Previous North Korea Nuclear Tests

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State leaders have ordered that four fluid-injection wells in eastern Ohio will be “indefinitely” prohibited from opening in the aftermath of heightened seismic activity in the area, an official said.

Ohio Department of Natural Resources Director James Zehringer had announced on Friday that one such well — which injects “fluid deep underground into porous rock formations, such as sandstone or limestone, or into or below the shallow soil layer,” the U.S. Environmental Protection Agency explains — was closed after a series of small earthquakes in and around Youngstown.

Then on Saturday, a magnitude 4.0 earthquake struck that released at least 40 times more energy than any of the previous 10 or more tremors that had rattled the region in 2011.