USGS: February quake likely caused by wastewater disposal

FAIRVIEW, Okla. (AP) – The third largest earthquake in Oklahoma was likely triggered by underground disposal of wastewater from oil and natural gas production.
The U.S. Geological Survey said in a report Monday that the magnitude 5.1 quake that struck northwest of Fairview in February was likely induced by distant disposal wells.
The USGS report indicated that in the area around where the Fairview quake occurred, the volume of fluid injected increased sevenfold over three years.
The Fairview temblor had been the largest event in the central and eastern U.S. since the magnitude 5.7 quake hit near Prague in 2011.
In September, the largest earthquake in the state struck near Pawnee with a magnitude 5.8. The relationship between that quake and wastewater injection is still being studied.