ENID, Okla. (AP) — A series of small earthquakes believed by seismologists to be caused by the underground injection of wastewater from oil and gas production continued to rattle northern Oklahoma on Saturday.

Four quakes occurred Saturday morning, the strongest being magnitude 3.3 about 4 a.m., southeast of Enid in an area about 85 miles-100 miles (137-161 kilometers) north of Oklahoma City.

Nearly two dozen quakes have been recorded in the area since Friday by the Oklahoma Geological Survey with the most powerful being magnitude 4.2.

No injuries or damage have been reported and geologists sa...