After years of official skepticism, Oklahoma’s government has at last embraced the scientific consensus that the earthquakes now rocking the state are largely caused by the reinjection underground disposal of billions of barrels of wastewater from fracking.
The state is now having an average of 2.5 earthquakes of at least magnitude 3 every day, when it used to average only 1.5 a year.
It isn’t the fracking that actually causes the earthquakes, but the disposal of the wastewater created during the process. Fracking companies pump this dirty water into the earth in a place with deep underground faults, so it doesn’t return to the surface. The theory is that this activity on the fault line lubricates Earth’s plates where they rub against each other, allowing them to move more freely, causing more frequent earthquakes.
The largest registered a magnitude 5.7. It injured two people, destroyed 14 homes, toppled headstones, closed schools, and was felt in 17 states. It was preceded by a 4.7 foreshock the morning prior and followed by a 4.7 aftershock. The home of Joe and Mary Reneau (less than two miles from the epicentre of the quake) took six months to rebuild
UK geology is thought to be more heavily fractured and faulted than that of the US, so we would expect more earthquakes from the same amount of activity, as the limited experience in Lancashire has shown.