There have been 40 earthquakes in Oklahoma over the past seven days.
The frequency of quakes in the state have increased by 50 percent since 2013.
Until fairly recently earthquakes in Oklahoma were a rarity, but due to fracking it has become one of the most active seismic areas in the U.S.
A report in March revealed that fault lines in the state dating back hundreds of millions of years had been recently reactivated and could soon lead to a devastating quake.
On Monday (27th July) alone, Oklahoma recorded five earthquakes. They were centered near Crescent, Oklahoma, though some of were felt in at least five other states.
Kake reported that the last quake was a 4.1 magnitude and was recorded around 8:20 p.m on Monday.
Earlier, a 4.5 magnitude was recorded around 1:12 p.m. and another with a magnitude of 4.0 was reported more than 20 minutes before at almost the exact location.
Scientists have said that seismic activity is being triggered by the injection of wastewater from booming oil and gas drilling operations into deep geological formations.
Eco watch reports: There was no reported significant damage from the earthquakes, but the rate of earthquakes in Oklahoma has increased by about 50 percent in the last two years, greatly increasing the chance for a damaging quake, according to the USGS. There have been eight quakes of magnitude 3.0 or larger near Crescent since Saturday and during the past seven days, Oklahoma has experienced about 40 earthquakes.
“Noticeable quakes—above magnitude 3.0—now hit the state at a rate of two per day or more, compared with two or so per year prior to 2009,” reports Reuters.
This spring scientists confirmed that the state’s recent uptick in fracking activity has led to a dramatic increase in earthquakes in the state, citing the injection into deep underground wells of fluid byproducts from drilling operations as the culprit. “Oklahoma experienced 585 magnitude 3+ earthquakes in 2014 compared to 109 events recorded in 2013,” according to the state’s website, Earthquakes in Oklahoma.
Last month, two more studies confirmed that the massive increase in seismic activity is linked to the state’s fracking boom. And Oklahoma may have surpassed California as the number one state for earthquakes, but it’s not alone in its dramatic increases in earthquakes. The U.S. Geological Survey has identified eight other states that have seen more frequent and higher magnitude quakes, as well, including neighboring New Mexico, Colorado, Kansas and Arkansas.
In response to the findings, the Oklahoma Corporation Commission Oil and Gas Conservation Division issued new directives this month expanding “Areas of Interest,” parts of the state that have been worst-hit by the quakes, and adding restrictions for 211 disposal wells. In March, the state required 347 wells to reduce their injection depths to above the Arbuckle formation because “there is broad agreement among seismologists that disposal below the Arbuckle poses a potential risk of causing earthquakes,” says the state.
“The Coordinating Council on Seismic Activity continues to evaluate and discuss what next steps should be,” said Michael Teague, Oklahoma secretary of energy and environment. “The Coordinating Council discussed the possibility of reducing injection volumes [of fracking fluid] in the near future, as recommended by recent scientific studies, as a potential next step.”