Link here.
Apparently there was an earthquake southeast of Williston: a 3.3 earthquake on September 28, 2012. The news is now starting to make the rounds. It takes a bit longer for news to travel in North Dakota. This was the first I heard of it -- a reader alerted me. Thank you.
Largest earthquake in North Dakota: 5.5 in 1909.
It looks like fracking, by micro-stimulation, lessens the likelihood of a large earthquake in North Dakota which could cause the state to fall into the Pacific Ocean. No tsunami alerts have been issued for the Missouri River.