The U.S. Geological Survey says several earthquakes have struck north-central Oklahoma, including one with a preliminary magnitude of 4.2.
Oklahoma Department of Emergency Management spokeswoman Keli Cain says there are no reports of injury or damage as a result of the Friday morning quakes near Stroud, about 55 miles (88 kilometers) northeast of Oklahoma City.
The 4.2 magnitude quake was recorded shortly before 9 a.m. and was followed by quakes of preliminary magnitude 3.8 and 3.7, in addition to smaller quakes of magnitude 2.9 and two of magnitude 2.7.
The Oklahoma Corporation Commission said its induced seismicity department and the Oklahoma Geological Survey are investigating the quakes.
Scientists have linked some oil and gas production in Oklahoma to an uptick in earthquakes, but the frequency of such earthquakes in Oklahoma had dropped recently as the state imposes new restrictions on the injection of wastewater underground.
Oklahoma experienced its largest-ever recorded earthquake in September, a 5.8-magnitude temblor centered in Pawnee.
July 14 quakes and aftershocks near Stroud, Oklahoma:
4.2 magnitude at 8:47 a.m. at depth of 5 3/4 miles.
2.7 magnitude at 9:03 a.m. at depth of 3 1/2 miles.
3.8 magnitude at 9:04 a.m. at depth of 4 1/2 miles.
3.7 magnitude at 9:17 a.m. at depth of 3 1/2 miles.
2.7 magnitude at 9:55 a.m. at depth of 4 miles.
2.9 magnitude at 10:04 a.m. at depth of 2 3/4 miles.
All the quakes occurred 6 to 8 miles north-northwest of Stroud, Oklahoma.
Source: U.S. Geological Survey.