Oklahoma has experience a roughly 900-fold increase in seismic activity since 2009, and is now the most earthquake prone region in the contiguous United States. Increased oil and gas activity, particularly wastewater from drilling for oil and gas, has been identified as a major cause of this rise. A new paper in Science by RFF’s Roger Cooke and coauthors Thea Hincks, Willy Aspinall, and Thomas Gernon provides a clearer picture of the causal relationship, and offers guidance to regulators seeking to cost-effectively reduce earthquake risk.
Using vine regression developed by Cooke, the authors identify injection depth relative to the interface between the crystalline ”basement” and sedimentary cover as a major determinant of earthquake risk. As Gernon, writes in The Conversation, “Raising injection well depths further above the basement rocks in key areas could significantly reduce the annual energy released by earthquakes, in turn making larger earthquakes less likely.”
By clarifying the connection between wastewater disposal and seismic activity, the study enables state regulators to explore more targeted—and therefore more cost-effective—approaches to reducing the risks of induced earthquakes in Oklahoma.