Oklahoma Hit By Largest Fracking Earthquake Since 2011
One of the strongest earthquakes ever recorded in Oklahoma hit the state on Saturday morning northwest of the town Pawnee. Buildings in the town have been damaged and a man has been taken to hospital with head injuries as a result of shielding a child from falling masonry.
Oklahoma has gone from almost no large earthquakes to pushing California into second place, as most seismically active state in the US. This has been caused by the use of thousands of injection wells to dispose of waste from unconventional oil production in the state.
The magnitude 5.6 main earthquake near Pawnee has been followed by at least 7 aftershocks ranging from 2.7 to 3.6. This rivals the 2011 magnitude 5.6 near Prague, Oklahoma in which two people suffered minor injuries, 14 homes had various levels of damage, and part of a university building collapsed.
In addition to injection (waste disposal) wells, earthquakes can also be caused by hydraulic fracturing of oil and gas wells, as happen to Cuadrilla’s first shale gas well in Lancashire. This appears to geology specific, with numerous cases in Canada but few in the US.