The use of hydraulic fracturing to open underground natural gas
formations has a low risk of triggering earthquakes, experts
reported Friday, but some scientists say the debate is far from
over. "Fracking," as the process is commonly known, involves
injecting a mixture of water and chemicals deep into the Earth.
The pressure causes shale rock formations to fracture, and
natural gas is released. The fluid is extracted, and the natural
gas is mined through the well. There's a higher risk of man-made
seismic events when wastewater from the fracking process is
injected back into the ground, according to a report by the
National Research Council, an arm of the National Academy of
Sciences. But out of about 30,000 disposal wells nationwide,
only a handful of noticeable tremors have been reported, with
the strongest equivalent to a magnitude-4.8 earthquake, the
panel of engineers and scientists concluded. Read the report
(PDF) Congress requested the study in 2010, as hydraulic
fracturing triggered a natural gas prod