August 27, 2011
Drilling for natural gas in Arkansas may have been associated with a series of small tremors there last year. Some have wondered, did hydraulic fracturing in the Marcellus shale have anything to do with this week's quake?
For starters, the quake's epicenter in central Virginia is more than a hundred miles from the nearest Marcellus shale drilling site. And Central Virginia does have a history of smaller quakes dating to the 1700s.
Still, the concept that humans can cause seismic activity does have credence.
Scientists think fluid pumped at high enough pressure can cause a layer of rock sitting on a fault line to slip, triggering an earthquake. In Arkansas, officials halted the injection of fracking waste into deep underground wells this summer after the wells were implicated in hundreds of small earthquakes there.
So did fracking have anything to do with the Virginia earthquake? Probably not. But could it cause others? Maybe. As for the Virginia quake, scientists say it will take months or even years before they can pinpoint its cause, deep underground.
For the Allegheny Front I'm Reid Frazier.