States that are using the recently popular technique of fracking (hydraulic fracturing) are seeing a dramatic increase in earthquake activity.
From 1978 to 2008, Oklahoma was struck with an average of two quakes of 3.0 magnitude or greater.
In the time period, June 2009 to June 19, 2014, there were 207 such quakes recorded in the state, the USGS said.
The increase began five years ago when 20 quakes of 3.0 magnitude or higher occurred, followed by 43 the next year and increasing every year except for 2012.
This corresponds with the beginning of fracking in the state.
Oklahoma now has more earthquakes than California.
Talk about a smoking gun…