Fracking Should Be Included in Earthquake Hazards Assessments, Scientists Say

US researchers and geophysicists with the US Geological Survey (USGS) are now including waste-water injection - including the "fracking" used in oil and gas development - to estimate earthquake hazards given the boom in earthquake incidents.

Efforts to include fracking in the equation stem from two earthquakes in 2011 that topped magnitude 5 and were suspected to have been triggered by waste-water injection - one in southern Colorado, at magnitude 5.3, and another in Oklahoma, at magnitude 5.7.

The average number of earthquakes per year with a magnitude of 3.0 or higher increased from only 20 several decades ago to more than 100 within the past four years, News Tonight Africa reported.

For now, researchers behind the project claim they aren't trying to determine whether recent earthquakes are natural or human-made, USGS researcher Justin Rubinstein said, although he and his team, as well as other researchers, are trying to find ways to tell the difference.

"Waste water is the dominant cause," Gail Atkinson, an earthquake scientist at Western University in London, Ontario, said, according to The Christian Science Monitor, "but what we are seeing as time goes on is that there are also events being induced from hydraulic fracture operations."

Fracking involves injecting fluids into oil- or gas-bearing rock formations to free oil and gas from reserves that otherwise would be hard to reach, and generates lots of waste water.

Data is limited in terms of underground fluid flows and the pace and volume of water being pumped into the ground at fracking sites, but the most important thing, researchers suggest, is not necessarily determining what's causing these earthquakes as much as how to mitigate them.

"To some degree, it doesn't actually matter whether or not these earthquakes are induced," Rubinstein added. "The increased rate indicates there is an increase in hazard."

The new assessment may tell scientists to what degree, if any, fracking plays a role in the earthquake boom. The federal government has left decisions on earthquake regulations for wastewater injection wells to the states, some of which have decided there is enough evidence to take action, according to The Bellingham Herald.