[10] Scientific studies attribute the rise in earthquakes to the disposal of wastewater produced during oil extraction that has been injected more deeply into the ground.
In March 2013, a peer-reviewed paper published by a research team led by seismologist Katie Keranen at the University of Oklahoma in the scientific journal Geology reported that "the volume of fluid injected into the subsurface related to the production of unconventional resources continues to rise" and that there was a link between the "zone of injection and the seismicity" potentially triggering the Prague earthquake.
[9] Research suggests that most of the significant earthquakes in Oklahoma since the 1930s may have been induced by oil production activities, primarily waste-water disposal.
With a USGS-assigned magnitude of 4.4 Mw, it resulted in two fall-related injuries,[27][28] and the USGS received felt reports from seven states.
Early on the morning of November 5, 2011, an earthquake with a magnitude of 4.8 struck an area east of Oklahoma City roughly centered between Sparks and Prague.
[33] For 2013, an estimated 109 earthquakes occurred according to the Oklahoma Geological Survey, a number substantially higher than in any previous year going back to 1978.
[35] The swarms, while initially located primarily further south, traveled northward from Central Oklahoma into Logan County in early 2014.
[39] For the first time, the United States Geological Survey decided it would include earthquakes believed to have connections to industrial activities in its National Seismic Hazard Map which sets standards for construction and insurance rates.
[40] According to USGS National Seismic Hazard Project head Mark Petersen, an updated version of the map would become available before the end of 2015.
This marks a deviation from the past, with the USGS updating the National Seismic Hazard Map annually instead of every six years.
Several months later in April 2015, a comprehensive assessment was released analyzing the link between the increase in seismic activity in the Central United States and oil and gas operations.
[42][43] On April 21, 2015, the Oklahoma Geological Survey abandoned its skepticism of the possible link between earthquakes and industrial activities and said in an official statement that it "considers it very likely that the majority of recent earthquakes, particularly those in central and north-central Oklahoma, are triggered by the injection of produced water in disposal wells."
On February 13, slightly over five weeks later, an earthquake with an estimated magnitude of 5.1 struck 28 kilometers (17 miles) northwest of Fairview.
[52][53] Multiple residential and commercial structures were damaged, and one person was injured in Pawnee when he was struck by falling bricks.
[14] A large earthquake of magnitude 5.0 occurred on the evening of November 6, with an epicenter located one mile (2 km) west of Cushing in Payne County.
[58] In March 2017, an updated seismic hazard forecast, which like the 2016 version included the risk from induced earthquakes, was released by the United States Geological Survey.
[66] More than 70 percent of the produced water from both plays is disposed through permitted Class II injection wells into the Arbuckle Group where it rests on Precambrian basement.
Fallin added, "We believe that by linking scientists and energy experts, we can develop sound regulatory practices and policies in our state while also alleviating any questions our citizens might have."
Holland had previously spoken with a senior official of the United States Geological Survey discussing the connection between a swarm of earthquakes near and east of Oklahoma City.
Holland wrote to USGS science advisor Bill Leith in 2013 "Since early 2010 we have recognized the potential for the Jones earthquake swarm to be due to the Hunton dewatering," but he followed by saying "But until we can demonstrate that scientifically or not we were not going to discuss that publicly."
In October 2013, a joint statement between the OGS and the USGS announced that "activities such as wastewater disposal" may be a "contributing factor to the increase in earthquakes."
Holland was requested a week later to come to Oklahoma Corporation Commission headquarters by then-Commissioner Patrice Douglas for a meeting.
[72] In the immediate aftermath of the September 3, 2016 earthquake near Pawnee, the Oklahoma Corporation Commission issued an emergency order shutting down thirty-seven waste water disposal wells in the immediate vicinity of the epicenter.
[73] Governor Mary Fallin also declared a state of emergency for Pawnee County, where the worst of the damage from the quake was located.
[74] On September 16, less than two weeks after the earthquake, the Oklahoma Geological Survey announced that it had hired a new state seismologist, Jacob Walter.
This was the second wastewater injection well directed to "shut in" or halt operations by the agency since a new monitoring system was established in 2013.
According to Matt Skinner, a spokesman from the commission, the directive was issued on February 3 in response to a magnitude 4.1 earthquake recorded in the area four days earlier.
"[77] As a result of the magnitude 5.6 earthquake on November 5, 2011, an estimated one million dollars in damage occurred in and around the Prague area.
The case was originally brought before a state court by Gary and Sandra Ladra, whose home in Prague was damaged; she had also sustained physical injuries during the quake.