A series of earthquakes near Youngstown, Ohio, were most likely caused by the underground injection of shale drilling wastewater, Ohio officials have concluded. "After investigating all available geological formation and well activity data, ODNR regulators and geologists found a number of co-occurring circumstances strongly indicating the Youngstown-area earthquakes were induced," the Ohio Department of Natural Resources said in a release today. "Specifically, evidence gathered by state officials suggests fluid from the Northstar 1 disposal well intersected an unmapped fault in a near-failure state of stress causing movement along that fault."