EDMOND, Okla.– At least six earthquakes, including two with magnitudes greater than 4, have been recorded near a suburb of Oklahoma City, according to the US Geological Survey.
Preliminary magnitudes of the earthquakes near Edmond include a 4.1 shortly after 5:30 a.m. on Saturday and a 4.4 around 9:45 p.m. on Friday.
No injuries or significant damage were reported, according to city of Edmond spokesman Bill Begley, who said investigators will fully inspect the infrastructure.
Four other earthquakes ranging from magnitude 2.5 to 3.2 were also recorded by the USGS Friday evening and early Saturday in the area about 15 miles northeast of Oklahoma City.
The threshold for damage usually starts at 4. The strongest earthquake on record in Oklahoma was a magnitude 5.8 near Pawnee in September 2016.
Oklahoma Corporation Commission spokesman Matt Skinner said the agency is investigating the earthquakes, which he said occurred in an area known as the Arcadia Field, where previous earthquakes have been linked to the underground injection of wastewater, a byproduct of the oil and gas production.
The injection wells were closed, Skinner said. “There is no oil and gas activity in that area that could be associated with these earthquakes” that occurred Friday evening and Saturday, he said.
Skinner said the area also lacks hydraulic fracturing, or fracking, the technique of extracting oil and gas from rock by injecting high-pressure mixtures of water, sand or gravel and chemicals.
Many of the thousands of earthquakes in Oklahoma in recent years have been linked to the underground injection of wastewater from oil and natural gas extraction.
The Corporation Commission, which regulates the oil and gas industry in the state, has ordered several producers to close some injection wells and reduce volumes in others due to the earthquakes.