Pennsylvania’s environmental regulators last month addressed a potential link between a string of small local earthquakes and hydraulic fracturing in the Utica Shale. The state’s Department of Environmental Protection (DEP) released a report in February analyzing together four small-scale earthquakes, which occurred in April 2016 in Lawrence County, and fracking operations in the surrounding area.

The relevant well pad, the report states, is located within five miles of most of the reported epicenters of the earthquakes. Fracking began at the pad almost a month before seismic activity was recorded in nearby townships.

Says the DEP in the report, “There is no definitive geologic association of events,” but there is “a marked temporal/spatial relationship” between the microseismic events and fracking operations.

The earthquakes, which ranged in magnitude from 1.8 to 2.3 on the Richter Scale and were largely unexperienced by humans, prompted the owner of the well pad to voluntarily cease operations at the wells. The company later indefinitely discontinued its fracking and stimulation operations at the pad—also voluntarily.

Should the owner wish to renew operations at the site, the DEP recommended that it change its method of stimulation, abandoning zipper fracturing, and employ a more stringent reporting schedule for similar seismic events. The company has agreed to adopt these recommendations.

DEP regulators also recommend that the company adopt these same measures in relation to any new permit requests it makes, and that other operators also adopt these measures in the area where the earthquakes occurred.

“Induced seismicity is a relatively new and complex technical issue,” said DEP Acting Secretary Patrick McDonnell. “This report reflects our commitment to understand what occurred, through extensive review with scientific and industry partners, and to formulate procedures to reduce seismic risk going forward.”

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