By injecting a mixture of water and chemicals
Fracking creates fractures in shale rock to release the fossil fuels trapped inside by injecting a mixture of water and chemicals at high pressure.
The technology has been widely adopted across the US, but in Europe the method is still controversial.
Earthquakes – both felt and unfelt – have increased over the past decade as the popularity of fracking has increased.
The drilling in Ohio was undertaken by Hilcorp Energy, which halted operations on 10 March after the 3.0 magnitude earthquake.
But the fact that no earthquakes occurred at nearby industrial areas suggests that the fault that was activated is limited in extent, concluded researchers.
The risk of earthquakes is frequently cited by anti-fracking campaigners as a reason not to embark upon the new method of extracting oil and gas.
Oklahoma’s fivefold increase in earthquakes during 2014 has led many residents to claim a link to the oil and gas rush. Well over 30,000 oil and gas wells litter the landscape, employing 1 in 6 of the state’s population.
Last year the Oklahoma experienced 564 quakes above a magnitude of 3.0. According to the EnergyWire website that makes it the most seismically active state in mainland US.