TONKAWA, Oklahoma — Parts of northern Oklahoma have been shaken by an earthquake.
The U.S. Geological Survey says the magnitude 3.3 temblor was recorded at 10:20 a.m. Sunday less than 11 miles southeast of Tonkawa in Kay County near the Kansas border. Geologists say the quake was recorded at a depth of about two miles.
No damage or injuries were immediately reported. Geologists say earthquakes of magnitude 2.5 to 3.0 are generally the smallest that are felt by humans and that damage is not likely from earthquakes below magnitude 4.0.
The Oklahoma Geological Survey has said it is "very likely" that earthquakes are being triggered by the injection of wastewater from oil and natural gas drilling operations across the state.