On December 2, 2016, the Associated Press released a statistical analysis showing that seismic activity in Oklahoma has dropped significantly since May 28, 2016, when the state ordered Class II-D Underground Injection Control wells to decrease injection volumes by 40%. Specifically, the AP reported that since Oklahoma ordered a 40% reduction in injection volumes, the state has seen a decrease of seismic activities of magnitude 3.0 or larger. The AP reports that prior to the reduction in injection volumes, the state experienced an average of 2.3 seismic events of magnitude 3.0 or larger per day. By comparison, the state averaged 1.3 seismic events of magnitude 3.0 or larger per day in November 2016, and just one such seismic event per year prior to 2009.
The AP analysis was released shortly after the journal Science Advances published a paper by Cornelius Langenbruch and Mark Zoback that detailed the findings of computer simulations of future seismic events in Oklahoma. According to Langenbruch and Zoback, their computer simulations show that seismic events in Oklahoma will continue to decrease to pre-2009 levels over the next several years.