It did indeed make the Mississippi flow backward for a brief time. Additionally, the quake caused the spontaneous formation of Reelfoot Lake in TN.
If you are ever at the Natural History Museum in DC, they have this seismic sensor that lights up everytime there is seismic activity somewhere. I couldnt beleive how many daily tremors occur here in MO. They are small to be sure, butthe potential for a big one here exists. In fact we have earthquake coverage as part of our homeowners insurance..