USGS attributes Oklahoma earthquakes to induced seismicity

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On March 7, the American Geophysical Union (AGU) Journal of Geophysical Research published a U.S. Geological Survey (USGS) sponsored study on the relationship between a November 2011 magnitude-5.0 earthquake and successive aftershocks along the Wilzetta fault in Oklahoma, including a magnitude-5.7 earthquake, the largest ever recorded in the state.

The study builds on a 2013 report published in Geology that links the magnitude-5.0 foreshock to fluid injection associated with oil and gas drilling. The recent USGS study concludes the magnitude-5.7 earthquake is the largest induced seismic event on record.

Low-magnitude earthquake frequency has increased in gas drilling states since 2010 and is considered to be linked to wastewater injection associated with oil and gas drilling.

The results of the study were announced on a USGS blog in January, before official publication by AGU.

Sources: E&E News; Geology; United States Geological Survey; Wiley Online Library