Ongoing hydraulic fracking operations will only exacerbate seismic activity, leading to heightened earthquakes in areas where wastewater is injected deep underground, according to new research.
To unleash natural gas, hydraulic fracturing - or fracking - requires large volumes of water, sand, and chemicals to be pumped underground. Scientists attending the Seismological Society of America (SSA) annual meeting said Thursday that this storage of wastewater in wells deep below the earth’s surface, in addition to fracking’s other processes, is changing the stress on existing faults, which could mean more frequent and larger quakes in the future.
Researchers previously believed quakes that resulted from fracking could not exceed a magnitude of 5.0, though stronger seismic events were recorded in 2011 around two heavily drilled areas in Colorado and Oklahoma.
“This demonstrates there is a significant hazard,” said Justin Rubinstein, a research geophysicist at the US Geological Survey (USGS), according to TIME magazine. “We need to address ongoing seismicity.”
Not all of the more than 30,000 fracking disposal wells are linked to quakes, but an accumulating body of evidence associates an uptick in seismic activity to fracking developments amid the current domestic energy boom.
The amount of toxic wastewater injected into the ground seems to provide some clarity as to what causes the earthquakes. A single fracking operation uses two to five million gallons of water, according to reports, but much more wastewater ends up in a disposal well.
“There are so many injection operations throughout much of the US now that even though a small fraction might induce quakes, those quakes have contributed dramatically to the seismic hazard, especially east of the Rockies,” said Arthur McGarr, a USGS scientist. The USGS researchers spoke with reporters via conference call on Thursday.
Scientists believe the cumulative effect of these operations could result in larger quakes becoming more common over time.
“I think ultimately, as fluids propagate and cover a larger space, the likelihood that it could find a larger fault and generate larger seismic events goes up,” Gail Atkinson, professor of earth sciences at Western University in Ontario, Canada, said at the SSA meeting.
Seismologists say that widespread oil and gas development in one area could create hazardous quakes in nearby areas not equipped to handle activity above a low-level quake.
“With these huge wells, the pressure they create can travel tens of kilometers,” said Katie Keranen, assistant professor of geophysics at Cornell University.
As fracking spreads to new areas like Ohio that haven’t traditionally experienced many earthquakes, the scientists said more research is needed to understand the risks involved, for policymakers and the public.
“There’s a very large gap on policy here,” said Atkinson. “We need extensive databases on the wells that induce seismicity and the ones that don’t.”
The scientists said energy industry players must offer more information on their fracking operations, and data on these actions must be made publicly available more often.
“There are minimums in terms of what needs to be recorded - injection pressure and volume - but these are only made available to the public once a year,” Rubenstein said. “We need more information reported more frequently to do the science correctly.”
Last month, state geologists in Ohio said the link between fracking and five minor quakes in the state was “probable.”
Outside of increased seismic activity, fracking has been linked to groundwater contamination, exacerbation of drought conditions, and a laundry list of health concerns for humans and the local environment.