Fracking rarely causes quakes, report says

WASHINGTON – The controversial practice of hydraulic fracturing to extract natural gas does not pose a high risk for triggering earthquakes large enough to feel, but other types of energy-related drilling can make the ground noticeably shake, a major government science report concludes.

Even those man-made tremors large enough to be an issue are very rare, says a special report by the National Research Council. In more than 90 years of monitoring, human activity has been shown to trigger only 154 quakes, most of them moderate or small. That’s compared to a global average of about 14,450 earthquakes of magnitude 4.0 or greater every year, said the report, released Friday.

Only two worldwide instances of shaking can be attributed to hydraulic fracturing, a specific method of extracting gas by injection of fluids sometimes called “fracking,” the report said.

Report chairman Murray Hitzman, a professor of economic geology at the Colorado School of Mines, said, “Is it a huge problem? The report says basically no. Is it something we should look at and think about? Yes.”