A record-tying earthquake on the edge of Oklahoma's key energy-producing areas rattled the Midwest from Nebraska to North Texas on Saturday, and will likely bring fresh attention to the practice of disposing oil and gas field wastewater deep underground.
The United States Geological Survey said a 5.6 magnitude earthquake happened at 7:02 a.m. local time on Saturday in north-central Oklahoma, on the fringe of an area where regulators had stepped in to limit wastewater disposal. That temblor matches a November 2011 quake in the same region, AP reported.
An increase in magnitude-3.0 or stronger earthquakes in Oklahoma has been linked to underground disposal of wastewater from oil and natural gas production.
According to an analysis published by Tulsa World in January, the volume of wastewater disposed rose 81% over six years, coinciding with the state’s increase in earthquakes.
The Oklahoma Corporation Commission, which since 2013 has asked wastewater-well owners to reduce disposal volumes in parts of the state, directed about 35 wells within an approximately 1,300-square-kilometer area around the epicenter to shut down within seven to 10 days because of previous connections between the injection of wastewater and earthquakes.
