Two earthquakes recorded within one minute of each other have shaken an area in north-central Oklahoma near the site near of a key oil hub.
The U.S. Geological Survey says the earthquakes occurred Tuesday in Cushing in Payne County, about 50 miles northeast of Oklahoma City.
The U.S.G.S. says the first 3.3 magnitude quake was recorded at 3:54 a.m. less than one mile north of Cushing. The second 4.0 magnitude temblor struck at 3:55 a.m. about two miles northeast of Cushing.
No damage or injuries was reported. Geologists say damage is unlikely in earthquakes below magnitude 4.0. A magnitude 5.0 earthquake earlier this month damaged homes and businesses in Cushing.
Scientists have linked an increase in earthquakes in Oklahoma to the underground disposal of wastewater from oil and gas production.