Two separate studies are providing insights into the earth-shaking consequences of the controversial gas extraction process known as fracking.
Both studies confirm that hydraulic fracturing, or fracking, can trigger manmade earthquakes. The process involves blasting water, sand and chemicals deep into the ground to fracture rock to obtain oil and natural gas.
The U.S. Geological Survey is set to release its findings Wednesday that a "remarkable" increase of quakes in the U.S. midcontinent since 2001 is "almost certainly" the result of oil and gas production.