Oklahoma rocked by large earthquake linked to fracking activities
08 November 2016
A significant earthquake, centred about 53 miles northeast of Oklahoma City, damaged dozens of buildings in and around the town of Cushing on November 7. There were no reported casualties in the earthquake, which was rated 5.3 on the Richter scale by the US Geological service. This is the third in Oklahoma this year with a magnitude of 5.0 or greater.
USCG 2016 earthquake forecast - Image: USCG
Oklahoma has recently become the most earthquake-prone state in the US which scientists say are due to the reinjection of wastewater as part of the fracking process. Oklahoma has suffered 138 earthquakes of magnitude 1.5 or greater in the past month alone, adding up to 2,199 over the past year — including its largest quake ever, one of 5.8 magnitude in September.
New earthquake modelling technology being used by the USGS suggests that the earthquakes are getting stronger in the state, with serious consequences if the progression continues unchecked.
The town is home to the Cushing Tank Farm, said to be the world’s largest oil storage facility with a capacity in excess of 100 million barrels. No leaks had been reported as of November 8, but Oklahoma Corporation Commission spokesperson Matt Skinner said the OCC was investigating the potential damage to oil pipelines heading to the Tank Farm.
When particularly strong quakes hit, the OCC directs well operators to cease wastewater injections, or reduce volume.
Last year, Reuters reported that one company with storage facilities in Cushing, Phillips 66, had changed its protocols to reflect the increased earthquake activity. The changes include new plans for "inspecting the health of crude tanks, potentially halting operations after temblors and monitoring quake alerts."
After the Cushing quake, Oklahoma Governor Mary Fallin declared a state of emergency for the county. The Oklahoma Corporation Commission (OCC), which oversees disposal wells, also directed all wells within 6 miles of Cushing to wind down injections over the next week and wells within 15 miles were ordered to reduce their injections.
The previous week, the OCC shut down wastewater wells north of Cushing after a magnitude 4.3 earthquake shook the town of Pawnee.
Following the growth of shale fracking operations, Oklahoma has recently become the most earthquake-prone state in the USA. Oklahoma has suffered 138 earthquakes of magnitude 1.5 or greater in the four weeks up to the Cushing quake, adding up to 2,199 over the past year — including its largest quake ever, one of 5.8 magnitude in September.
Energy companies produce toxic wastewater during oil and gas production. To keep it from contaminating drinking water near the surface, they inject the wastewater into deep disposal wells. These can put pressure on faults in the earth's crust, causing them to slip, which in turn causes an earthquake.
Two years ago, a team of USGS scientists found “several lines of evidence” directly linking an increase in Colorado and New Mexico earthquakes since 2001 to wastewater injection used in both shale fracking and conventional oil well drilling.