There isn't a mountain specifically named "Fault Mountain." It's likely you're thinking of a fictional location, possibly from a book, movie, or game.

Could you provide more context?

* What is the source of your information? (Book title, movie, game, etc.)

* What is the story about?

* Are there any other details about the mountain you can remember?

With more information, I might be able to figure out what you're referring to.