On November 5th, you may recall, the largest earthquake in Oklahoma's history occurred just 30 miles East of Oklahoma City.
Oklahoma is a hotspot for fracking (hydraulic fracturing to recover oil in shale formations miles deep).
Oklahoma experienced between two and six earthquakes a year between 1972 and 2008, before fracking.
In 2010, after fracking, it experienced one thousand and forty-seven!
[Read more at Reader Supported News where I got this information from.]