Well, this is a nightmare place of traditional dimensions. Some 3.9 kilometers of rock above you; the air around you hot and dark; the rocks crushing you in 50 degrees Celsius hot or more. Some 800 kilometers of caverns and tunnels crawl everywhere, striking downwards like an inverted tree of one thousand knife branches; thousands and thousands of people shuffle tired here and there working, ever going deeper.
The name of the place is the TauTona (“Great Lion”) gold mine, in South Africa, or rather under South Africa. Pretty much a place I do not want to go to.
Imagine an underground earthquake causing a collapse about a kilometer above you; the electricity goes, and you can just wait as your lamps fail, and as your air conditioning fails and the temperature creeps up from merely hot to uncomfortable to worse, to 55 degrees Celsius; as you wonder how long your air will last; and for all you know there may be several kilometers of collapsed rock between you and anyone that can help you out.
Actually, don’t imagine that. May cause loss of sleep. Try to imagine something more cheerful. Um, like…
Well, the first thought that came to my head was a plot for a novel. One day there’s something that the people deep down in the mine think is a quake or a collapse above them; they lose all contact with the ground level, and after sitting very still and breathing very quietly for a few hours decide that they want out, weak rock above or no. Going up they still fail to re-establish contact with the ground level, but find only minor rockfalls and similar problems.
(Or maybe they have to walk the whole way up through the smaller shafts because the lift has broken, raining a few kilometers of glistening and thundering steel cable on the heads of those waiting for it?)
Something terribly wrong upside, though, and they don their breathing apparatuses as they go upwards because the air doesn’t seem to be getting any better. (Caveat: I have no idea if they use such in such mines, but dramatic licence and marginal plausibility and all that.)
They — and depending on the kind of a story this would be, this “they” would be a night crew of a few dozen, or the whole complement of a few thousand; and forget not the panicking and hysterical and reluctant ones — they finally get up, and find that something a whole lot worse than a rockfall or earthquake has taken place. Through careful building it is horrifying yet not altogether surprising that the ground level has been replaced by a smoking ruin — buildings blown away, everything covered by soot, skies black, everything gone, all living things not dead but disintegrated by fire and wind and worse.
No, not by a nuclear war! That’s the nightmare of yesterday, and no doubt has been done like this already, probably several times. (Though someone should crank out a short story of the typical action mold but different resolution: a submarine receives orders to launch nukes; origin of orders dubious, HQ impossible to contact; a grimly obeisant captain overpowered by a non-apocalyptic crew who doesn’t want to start the end of the world; sub surfaces in New York harbor, finds the world has actually been destroyed by a nuclear war. Orders were genuine after all. Ha-ha; in your face you moderate people, you.)
Besides a nuclear armageddon is small potatoes to what I have in mind — a cosmic catastrophe! Take up Phil Plait’s Death from the Skies!, and pick anything that can scour off everything on Earth to the depth of a few kilometers. Not something that just wrecks the atmosphere, or smashes Buenos Aires; no, something that cauterizes the whole planet! (Dubious plus side: no lingering radiation — if at all possible — so our plucky “survivors” will keep on being the last living things on a dead world until they starve or go mad.)
Now, if one was writing something like this as a short story, it would end in that realization; the problem would be finding a non-hokey way of communicating just what had happened. (“Suddenly Norm recalled talking to his astronomer brother in Brighton the night before. Clyde had been going on about some supernova candidate or the other…”)
If, on the other hand, one was doing this novel-length, it wouldn’t do to do 300 pages of heroic upward struggle, and then end on such an alien note. But what then?
Here my memory of astronomical disasters fails me, but even if the event was short and only one half of the planet was scoured, the remaining half wouldn’t be in any condition to send help soon; see the problems of having half of the Earth’s atmosphere pretty much blown or broken away, winds, storms, earthquakes, tsunamis, and similar little things. So no rescue.
There might be other survivors, maybe in relatively nearby mine shafts; looking for them could occupy some time, at least if you pulled the obvious string of “But my wife’s down there! Unless she was cremated along with Cape Town!” — but after that the only possible other survivors would be deep sea divers, who wouldn’t add much to the story except a functioning vehicle. (Though I have no idea what my vague blast would do to the oceans, and whether that could be survived by water or by the sub. And would Catastrophe-X break water into highly flammable hydrogen and monstrously fire-enhancing pure oxygen? Oy vey, Hindenburg Atlantic!)
Starting a civilization all by themselves would be both doughty and futile: something that fries everything down to the depth of a few kilometers won’t leave any plants or animals alive. Not even tardigrades. (Assumption, to be fudged in some way: Wouldn’t be very story-conductive if they were met coming up by a fall of molten lava coming down; one would have to devise a disaster that left some non-molten ground to walk on.)
Then again, maybe one way to go is to give them something that remains. The obvious choices would be a) something inexplicable, and b) a military installation of research into implausibly advanced science. (“The third day — by their clocks anyway — up from the depths, Zuma and a couple of his gang came running to the camp, telling there was something weird a few kilometers to the west, behind the slag hills: a hemisphere of smooth, unburned rock bulging up from the ground, as if the stone around it had been blown away by the end of the world, but it had been kept whole by some sheltering force, stretching outwards half a kilometer from some underground point zero. Either worst or best of all, Zuma told the assembled survivors that there seemed to be an entrance of some sort atop the unnaturally geometrically simple shape; a cut-off lift shaft into something that had been deep underground, or something like that.”)
(Yeah right original — a General Products hull by a different name.)
Come to think of that, the military survivors could be used to drop some heavy infodumps on just what had happened upside: CNN on the coffee room TV in the deep underground bunker, and the sudden news update on weird astronomical and atmospheric phenomena, quickly cut off by the atmosphere’s tumultuous demise; military emergency broadcasts just long enough to tell that all shit indeed breaketh loose, and does so all over the world, and mankind uses its last few moments for going crazy; and nations cry as by the unstoppable rotation of the Earth ever new areas are brought under the searing fire from space; and then silence, then hours and hours of shivering inside an opaque sphere that shouldn’t be that way unless the very powers of hell and heaven are battering at the world outside. When the military and scientific personnel finally get to peer out, they find that outside their safe haven all has been eaten away, even solid rock to a depth of a few hundreds of meters, leaving them stranded inside a hemispherical hill centered on their marvelous and diabolical device.
The problem here would be that such utter destruction would make rebuilding things nearly impossible (Well, there’s that seed vault in Spitzbergen; luck going there over boiled-away seas), and as the event had been an astronomical (and astronomically unlikely!) accident, there would be no space alien invader to fight, defeat, and avenge one’s world on; or to beg for help.
Watching the survivors disintegrate, lose hope, and starve to death wouldn’t be very entertaining either. (Well, it would be, up to a point. Especially when they realize the atmosphere is so degraded that climbing up a hill is enough of “Into Thin Air” for suffocation!)
It would seem that only really outre resolutions or continuations would work after that — an alien spaceship arrives to make a first contact but finds the planet much more vacant than it expected (much tragedy and some comedy there); some force or entity arrives to conscript the choiceless survivors into its time- and space-spanning plans (As apparently in “Air Raid” by John Varley: passengers of doomed airliners stolen to become far-future colonists); or something like that.
Going wild and introducing a time machine (!) in the military compound would be useless for heroics: you can’t save a world from something like what happened! “Quickly! Get everyone and everything of value at least five hundred meters underground!” I won’t even discuss harebrained plans of putting something between the Earth and the blast; what would be big and hardy enough, and movable? Supposing the origin-point (star?) of the disaster is very far relative to solar system distances, you’d need something almost Earth-sized to have Earth in its shadow to keep it from frying — you’d need a movie for that to fly! (“My brother Clyde has been working on something called red matter — and he has a space shuttle!”)
Then again, if one suffered the time machine, there would be a really bleak ending in the survivors all jumping decades into the past, determined to keep quiet and live their lives out in the last years of the planet Earth; they can’t save it, but at least they can have some fun in the world while it still exists. (And end the novel with the narrator saying “So this is the story of my life; how about yours? And oh, don’t make it longer than three months, five days and seven-odd hours.”)
Since a time machine smacks of cheating (time machines are like God: suppose one, and paradoxes abound!), something else would be a more realistic (though less striking) ending — preferably something else than “And then they all died THE END”.
If one wanted to really hurt the reader, the story would have the narrator putting down the book he’s been recounting this centuries-old account from, and while around them a second civilization spreads, a child would ask: “But Grampa, how did they survive after that? How did they become us?” — and Gramps would, as the readers howled in inarticulate rage, end the book with a wink and a “well, that’s a story for another day, little one.”
Then again, I think (have it; haven’t read it yet) The Fog by James Herbert is a fairly apocalyptic story that largely consists of inventive ways people can die in very special circumstances; you could play the star disaster idea like that, and end it like Dr. Strangelove: valiant bungling tries, but no dice. (“So what’s the book about?” — “It’s about how everyone dies.” — “What, everyone?” — “Yes.” — “Please don’t say you laughed reading it.”)
Then again, it is well said that wild ideas are easier than their execution; and I know I know so little about astronomical events, deep mining, human psychology and similar necessary subjects that it doesn’t make sense for me to go about trying something like this. And thereby, and with too much fanfare, have the idea if you want and run with it, you whoever you are; I don’t intend to use it.
But what was I saying? Oh yes, a four-kilometer deep mine. Pretty scary, if you ask me. And please don’t note the above plotting came about from the words “imagine something more cheerful”; I kind of failed there.