Hi Canie-
Lucifer`s Hammer is quite a story. I bought it back in 1977. The authors either did a lot of research or lived in the area depicted in the latter part of the story. From about Bakersfield north to the Tule River drainage every road and landmark they mention is right where they say it is. Including that "cave" near the soda spring and the old Morehouse Fish Hatchery just below Camp Nelson. The only landmark I can remember they got wrong was the nuclear power plant out by Taft. It was proposed but never built.
Tongue-in-cheek warning to any surfers: Don`t go surfing around Santa Monica- Malibu area during any pending comet impacts. That real tall building on west edge of Santa Monica could really ruin your health.
Oh, wasn`t the story about a comet that "calved"? Maybe it was an asteroid that calved?
Even though the story is fiction, the human reaction to such a large disaster is well worth studying. It could apply to any disaster, including major earthquakes.

Byron