According to a new study from the US Geological Survey, the great American flyover states from Colorado to Kentucky experienced an "unprecedented" increase in the number of 3.0 or greater magnitude earthquakes in 2011. In fact, last year the middle of the country saw six times more 3+ quakes than any average year in the 20th century.

So, what's causing all this trembling in the middle of the country? Well, it's not the same spiteful deity that has been attempting to smite us godless coastal types since the dawn of time. Rather, it appears to be caused by middle Americans themselves. In places like Oklahoma, where seismic activity has gone from a yearly average of 1.2 quakes per year to 25 per year since 2009, there's no volcanic activity to shake things up and account for the jump. According to the Atlantic, however, that increase directly coincides with the increased use of new oil and gas extraction techniques such as the dreaded fracking.

As activists at the Environmental Working Group point out, 400,000 new wells were drilled in the affected states between 2000 and 2010. That's 65% more than in the 90s, before the beginning of this shaky trend. Scientists at the USGS aren't ready to pin the blame on fracking or drilling just yet, but they do agree with environmental groups on one thing: that the increase in seismic activity is "almost certainly manmade".

The study itself will be presented at a seismology conference later this month. In the meantime, geological nerds can check out an online abstract.

[Atlantic]