Perhaps I am not giving American young adults enough credit, but I assume many would think of Lovecraft and his spin-offs before Greek mythology. And while he was using it as a negative, I don't think he intended to evoke tentacled creatures, or the lava-dwelling demon from Quake. Also isn't there a Chthon who's a bad-guy in one of the comic-book universes?
Edit: looked it up on wiki -- he's a god in the Marvel universe.