Fracking Linked to Series of Earthquakes in Ohio

It turns out that hydraulic fracturing, known commonly as fracking, may be triggering earthquakes. Scientists have found that fracking caused a series of small earthquakes in 2013 on a previously unmapped fault in Harrison County, Ohio.

Between Oct. 1 and Dec. 13, nearly 400 small earthquakes occurred in Harrison County. These included 10 "positive" magnitude earthquakes though none of these were reportedly felt by the public. The 10 positive magnitude earthquakes, which ranged in magnitude 1.7 to 2.2, coincided with fracking practices at nearby wells.

Fracking is a method for extracting oil and gas from shale rock. Essentially, it involves injecting water, sand and chemicals under high pressure into rock to create cracks. These cracks then lead the oil and gas to the surface where it's extracted. Yet creating these cracks can also result in micro-earthquakes.

"Hydraulic fracturing has the potential to trigger earthquakes and in this case, small ones that could not be felt, however the earthquakes were three orders of magnitude larger than normally expected," said Paul Friberg, co-author of the study, in a news release.

The earthquakes actually revealed an east-west trending fault that lies in the basement formation at approximately two miles deep and directly below the three horizontal gas wells that were being used. Later analysis actually identified 190 earthquakes during a 39-hour period on Oct. 1 and 2 just hours after fracking began at one of the wells.

"As hydraulic fracturing operations explore new regions, more seismic monitoring will be needed since many faults remain unmapped," said Friberg.

The findings reveal a bit more about how fracking can impact the surrounding environment. This, in turn, can provide more information to those involved in fracking operations.

The findings are published in the journal Seismological Research Letters.