Confirmed: Fracking practices to blame for Ohio earthquakes
From NBC News:
Wastewater from the controversial practice of fracking appears to be linked to all the earthquakes in a town in Ohio that had no known past quakes, research now reveals.
The practice of hydraulic fracturing, or fracking, involves injecting water, sand and other materials under high pressures into a well to fracture rock. This opens up fissures that help oil and natural gas flow out more freely. This process generates wastewater that is often pumped underground as well, in order to get rid of it.