Research linking Oklahoma’s 2011 magnitude 5.7 earthquake to the state’s oil and natural gas activity was published this week in the Journal of Geophysical Research.
The paper, co-written by former University of Oklahoma seismologist Kathleen Keranen, found that an earlier 5.0 earthquake near Prague was linked to a water injection well and that the first tremor likely triggered the state’s largest-ever quake less than 24 hours later. Her findings were reported initially a year ago.
“There appears to be a strong correlation between the wells that are injecting waste water in Lincoln County and the earthquakes in 2011,” Keranen told The Oklahoman in March 2013 when the report was completed.
Keranen now is an assistant professor at Cornell University. Her paper has since been peer reviewed and published.
“If this hypothesis is correct, the M5.7 earthquake would be the largest and most powerful earthquake ever associated with waste water injection,” the U.S. Geological Survey said Thursday.
The Oklahoma Geological Survey, however, has not drawn a connection to the oil and natural gas industry or any other man-made causes. Oklahoma Geological Survey seismologist Austin Holland has said the Prague quake appears “consistent with a natural earthquake.”
What’s to blame for recent quakes?
More than 220 earthquakes magnitude 2.5 or higher were reported in Oklahoma in 2013 — more than any other year in state history.
The state and national geological surveys have set up seismographs throughout the state and continue to study the ongoing earthquake swarm. The researchers are looking at possible links with water injection wells, but they also point out that such earthquake swarms have occurred in states like Idaho where there is no oil and natural gas activity.
The Oklahoma Corporation Commission is scheduled next week to consider a rule change that would require disposal well operators to provide regulators with more information.
Oklahoma is dotted with more than 4,500 private and commercial water disposal wells. More than 6,600 enhanced recovery wells throughout the state are used to pump water into a producing rock layer in an effort to push oil through a rock formation.
Injection and disposal wells have been used for much of the state's history. While oil and natural gas activity has picked up in Oklahoma in recent years, oil and water production still pale compared to levels seen in the 1980s and 1920s.
“Crude oil and natural gas are produced in 70 of Oklahoma’s 77 counties, so any seismic activity in the state is likely to occur near oil and gas activity,” Oklahoma Independent Petroleum Association spokesman Cody Bannister said Thursday.