Unlike the earlier quakes around Youngstown that were thought to be connected to the disposal of the wastewater composed of sand, water and chemicals that result from the shale fracking process, the March quakes around Poland in Mahoning County are believed to show a "probable connection to hydraulic fracturing near a previously unknown microfault," states the Aril 11 press release from the Ohio Department of Natural Resources (ODNR).
ONDR ordered work halted at seven area wells on April 7 "near the Pennsylvania border after the two earthquakes earlier in the day. The quakes, of magnitude 2.6 and 3.0, caused no damage or injuries but were felt in nearby towns," writes Henry Fountain.
Mark Bruce, a spokesman for the department, said it was too early to determine whether drilling operations induced the earthquakes. “What we’re focusing on now is getting all the data from the company,” he said. “We’ll examine it first and decide next steps after that.”
Fountain elaborates on the wastewater disposal considered to be the more prevalent and serious cause of fracking-induced earthquakes.
Over the past decade, shale oil and gas production has been linked to earthquakes in Ohio, Arkansas, Oklahoma and other states, and in several countries. In most cases, however, the quakes were tied to disposal wells, in which wastewater from oil and gas production is injected under pressure into permeable rock formations. The water is thought to alter pressures underground and unclamp old faults, allowing them to slip.
The video, "Man Made Quakes" that accompanies the article illustrates the fracking wastewater connection.
In addition to halting drilling at the seven wells, ODNR is requiring that seismic monitors be installed "for horizontal drilling within 3 miles of a known fault or area of seismic activity greater than a 2.0 magnitude," states the press release. If significant seismic activity is recorded, a moratorium could be put in place while ODNR develops "new criteria and permit conditions for new applications."