The quake, which struck 14 km (9 miles) northwest of Pawnee in north-central Oklahoma at 7:02 a.m. CDT (1302 GMT), had a magnitude of 5.6, matching in strength a temblor that hit the state in 2011, the USGS reported on its website. There were no immediate reports of injuries.
The earthquake, which had a depth of 6.6 km (4.1 miles), could offer fresh ammunition to environmentalists concerned about the side-effects of oil and gas production, which has been blamed for a spike in minor to moderate quakes in the region.