[Sgt_Schultze]

...important questions surround the process of injecting millions of gallons of water laced with chemicals (some of them not publicly identified) deep into the earth to make natural gas embedded in shale formations accessible. What, for example, does this do to groundwater and air quality?

It's the "deep into the earth" that strikes me. Maybe I'm mistaken, but I wasn't aware the groundwater was present at the depths these fracking companies operate. Below is an image from wikipedia indicating the fracking is below aquifer levels.

[Lx]

According to my vast research on earthquakes (I saw the movie Earthquake with Charlton Heston), since there’s a fault line, shouldn’t one side of the fault line have all the layers shifted in one direction or other?