Study Links Hundreds Of Ohio Quakes To Fracking

A new study suggests that fracking triggered hundreds of too-small-to-be-felt earthquakes in eastern Ohio late last year, months before the state first linked seismic activity to the oil-and-gas extraction technique. The study, in the journal Seismological Research Letters, identified nearly 400 tremors on a previously unmapped fault in Harrison County between Oct. 1 and Dec. 13, 2013. That included 10 quakes of magnitudes of 1.7 to 2.2 - significantly more intense than expected, though still minor. The quakes fell along a fault lying directly under three hydraulic fracturing operations and tended to coincide with nearby activity. A spokeswoman for the Ohio Department of Natural Resources says the state installed sensitive seismic monitors in the area over the past year and is keeping close watch.