Howard Gordon was inspired to write the story after seeing two news reports about Project Dante, a robotic explorer created by NASA that had been sent into a volcano.
The real Mount Avalon is located in Grafton County in the White Mountains of New Hampshire. The show's Mt. Avalon is a set somewhere in the Cascades range, presumably between Washington and Oregon.
The set used for the exterior of the field base camp was later sold to the production company responsible for the TV series The Sentinel (1996).