Tuesday, November 05, 2013

Oklahoma earthquakes seen linked to oil and gas; seismologist disagrees with assessment

Earthquakes that have been rocking the area around Oklahoma City since Saturday could be linked to oil and gas production sites, either from injection wells for drilling waste or removal of large amounts of oil and water, Mike Soraghan reports for Environment and Energy News. Officials recorded 16 earthquakes on Saturday, beginning with a 3.7 magnitude quake at 4:30 a.m. More earthquakes have been reported in the days since, with Earthquake Track recording a 3.2 magnitude quake this morning in Edmond, 15 miles outside Oklahoma City.

Over the past several years, seismologists have recorded hundreds of small quakes in the area, Soraghan writes. Katie Keranen, a Cornell University professor who has studied the tremors, "said the quakes appear to be linked to oil and gas activities in the area," Soraghan writes. Keranen told him, "These most recent earthquakes highlight the continuing seismic activity near Jones and the east Oklahoma City metro area, in a swarm which appears linked to high-volume water production and injection wells in central Oklahoma."

Kearnen "has also linked Oklahoma's largest recorded earthquake, a 5.7 near Prague in 2011, to nearby oil and gas waste injection wells," Soraghan writes. She presented her findings last month at the the Geological Society of America, saying, "Earthquakes began soon after the onset of injection. There are commonalities in the methods used for petroleum extraction from carbonate reservoirs in central Oklahoma, involving the production of high water volumes, which speculatively may explain the abundance of induced earthquakes recorded here."

Austin Holland, research seismologist with the Oklahoma Geological Survey, disagreed with Kearnen's findings, telling a local news station, "We know why Oklahoma has earthquakes. It's responding to these large regional stresses that are much smaller than in California, where you can better measure the deformation on a fault." (Read more)

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