I was wondering about this as of late:
How could someone survive a meteor impact? One the size of the K-T meteor?
IIRC such an impact might kill a majority of life on the planet-but not all. How could the human species survive? And if not the species, how could my family, friends, and I?
My very survival may depend on your answers…
Leave the planet.
It’s the same deal as surviving the nuclear winter. Dig a hole, line it with concrete, fill it with guns and beef jerky, then freeze to death because you forgot to move to the tropics.
Assuming that you’re not within a few hundred kilometers of the impact, in which case you probably wouldn’t be able to survive no matter how well prepared you are, Desmostylus is roughly correct. It’d be like surviving WW III, except (hurray!) no radiation. You want to be underground for the impact and its immediate aftermath, when the Earth’s atmosphere is heated to temperatures equivalent to the inside of an oven, wildfires rage, and civilization is destroyed.
[Caution, the following is about 40% Educated Guess, 40% Wild-Ass Guess, 10% Science Fact and 10% Complete Hooey.]
The trick after that is surviving the next year or two without the benefit of Walmart, cable TV, and sunlight. Temperatures at the surface will drop drastically (they call it an impact winter for a reason) so you’ll probably want a buried shelter and a power supply. (A few kg of plutonium would be extremely handy. Shop now to avoid the Christmas rush.)
Without photosynthesis, a goodly portion of the plants will die off, and the larger herbivores not killed in the initial blast will starve, followed quickly by their predators, including you and yours, if you don’t think ahead. Smaller critters will probably be able to eke out a meagre existence, in greatly reduced numbers, but unless you want to live on a dwindling diet of roast groundhog and field mouse for two or three years, I’d recommend laying in lots of supplies, including water, as all the rain will nasty acid rain due to all the soot in the atmosphere. For the same reason, don’t plan on doing any fishing. The aquatic species that aren’t starving will be dying due to the change in pH. It’d probably be well worth your while to do some research on edible insects.
You’ll probably want to have some seeds stored away so that you can begin rebuilding a primitive agrarian economy when the sun comes out. I’d definitely lay in some soybeans and other legumes, 'cause Bossie ain’t likely to make it through Armageddon.
Which begs the question of why you’d want to survive a impact so severe that it kills off everything else on Earth.
OTOH, it pays to be prepared on the off-chance that someone decides to turn the Moon into a tourist resort.
What you need, really, is a lot of money.
With sufficient funds it would be quite technically feasible to build a large underground shelter with a self-sustaining power sources and enough room for years of supplies for you and your family. You’d need lots of canned and dried food, medical supplies, a water recycling system and lots of water, a way to dispose of waste (dumped out the bottom of the shelter into a septic tank would be an easy solution.) You’d also have to ensure your shelter had access to the outside that could not be blocked off by ash or other fallout-type debris, but at the same time would seal your shelter. And your shelter would have to be in suitable ground - dug out of soft rock, preferably.
None of this is a technical mystery. But it would be extremely costly. I mean, depending how many people you’re going to hide out with, you’re talking about building a house underground with self-contained power, atmosphere recycling, and water recycling systems, sufficiently insulated and cooled to save you from the holocaust. It’s a lot of equipment, a lot of digging into rock, and a lot of engineering. Millions of dollars, I’d say.