This is a more theoretical option, but one also worth exploring.
The civilization can be relatively near, but most people don't like to live permanently underground.
Some risks are practically absent, and most weather/related problems can be ignored. Should the apocalypse come, one has a place to hide away. Earthquakes and other geological phenomena, as air supply become crucial.
Preventive measures/solutions: solid architectonic work required, life-support technologies are useful.
An eccentric created with a few friends and followers an underground complex some 300,000 cubic feet large, based on his visions. It persisted in secrecy for about 14 years, until the Italian government learned about it. See also Federation of Damanhur.
(more examples and attempts???)