HOUSTON — Earthquakes that shook an Ohio town last year are linked to hydraulic fracturing, according to a study published in a scientific journal Tuesday.
In March 2014, five recorded earthquakes of 2.1 to 3.0 magnitude happened within 0.6 miles of a group of oil and gas wells in Poland Township, Ohio operated by Houston-based Hilcorp Energy, which was conducting fracturing operations at the time, the study said.
Hydraulic fracturing involves treating oil and gas wells with a mix of water and chemicals at high pressure, causing underground rock to fracture and allowing oil and gas to flow more freely.
Typically, that process results in “micro-earthquakes” much smaller than humans feel, and it’s rare for fracturing to cause larger quakes, according to the authors of the paper, a pair of researchers at Miami University of Ohio.
But in this case, the results were more significant. State regulators reportedly ordered Hilcorp to stop all its operations in Poland Township in the wake of the earthquakes.
Researchers examined seismic data from the region and determined that while the fracturing didn’t create new faults in the earth, it activated a fault that wasn’t previously known, likely prompting the earthquakes.
The study was published by the “Bulletin of the Seismological Society of America”, a journal of scientific research on earthquakes.
While the community reportedly only felt one earthquake — the March 10 temblor that measured 3.0 — the researchers identified 77 earthquakes that ranged from 1.0 to 3.0 from March 4 to March 12 in the area.
A Hilcorp spokesman said the company is still evaluating the study and was unable to comment on its specific findings. “However, Hilcorp is committed to conducting all of its operations in a safe and responsible manner and will continue to participate with various state and federal regulatory bodies and other stakeholders in the ongoing efforts to further study and understand the issues related to induced seismicity,” company spokesman Justin Furnace said.
The scientists found that the earthquakes coincided with fracturing activity, based on well stimulation reports published by the state.
“We just don’t know where all the faults are located,” said Robert Skoumal, a doctoral geology student who co-authored the study with geology professors Michael Brudzinski and Brian Currie of Miami University in Ohio. “It makes sense to have close cooperation among government, industry and the scientific community as hydraulic fracturing operations expand in areas where there’s the potential for unknown pre-existing faults.”