"Advanced drilling and hydraulic fracturing technologies, especially since 2008, have enabled large-scale oil and gas production in lower-permeability rock such as shale," the EIA writes. "Tight oil and shale gas plays span much of the continental United States and include both new and well-established oil and gas drilling locations."

Indeed, the American shale boom has been a source of excitement as it has been a source of new jobs, economic growth, and energy independence.

But with oil and gas prices crashing, many of these shale plays have become uneconomical, stoking fears of fiscal and economic problems in energy-driven states like Texas, North Dakota and Alaska.

For reference, here's where the major shale plays are across the continental US.