Apart from famously creating Reelfoot Lake, when it went off last time, it also caused violent geysers of sand to erupt across West TN, Eastern Arkansas, and the Missouri Bootheel. It left the scars of these geysers across the region where vertical columns of sand come all the way to the surface and left a "fallout zone" of the sand across the surface in areas. It's really cool to see them up close if you know what you're looking for. The whole region is on top of miles of sand, with silty topsoils overlaying them from river deposits and windblown silt from the plains due to massive sandstorms during the glacial period. But there's some spots where there will be a circle of sand with very little topsoil on the surface and a streak of sandier soil in one direction away from that spot. That's the geyser and the fallout.
I'm prepared for nerd-bashing.