A United States Geological Survey document released Thursday documents an increase in earthquakes likely caused by human activity, mapping 17 seismically active pockets in eight states. The document is not a study of the causes of the quakes, but rather the preliminary result of an initiative to model and predict future seismic activity; it does note that there has been a "substantial increase" in quake rates since 2009 and that the increase is attributed by other studies to the "injection of wastewater or other fluids in deep disposal wells." Wastewater injection is a technique often associated with hydraulic fracturing. Here's the USGS map of affected areas:
Officials in Oklahoma said on Tuesday that it is "very likely that the majority of recent earthquakes" in their state "are triggered by the injection of produced water in disposal wells." In context, that's a strongly worded statement, and it was described as "significant" by Republican governor Mary Fallin, who also added that "state agencies are already taking action to address this issue and protect homeowners."