I'm building a post-apocalyptic setting where the cataclysmic event is a volcanic eruption from Yellowstone that releases a blanket of ash that reaches from California to just before the Midwest. Earthquakes are also felt across the world, many demolishing major urban centers. I'm hypothesizing a volcanic winter that would last some decades, resulting in (of course) the collapse of most civilization and the extinction of much of humanity.

My question here is pretty broad, but is it viable that (parts of) humanity would survive such an event, and what would be the extent of damage to nature both in the ash-covered areas and the surrounding landscape? How long would/could it take for the winter to lapse? Could it last up to 50 years, with a resulting long epoch of cooling, of course? Would humanity be able to survive that?

  • $\begingroup$ Just a continuity point, the prevailing winds blow to the east, it is likely Chicago would see more ash then Sacramento. $\endgroup$
    – Jon
    Oct 3, 2014 at 17:58
  • $\begingroup$ Volcanoes can eject the particulate far above trade wind levels though, no? $\endgroup$
    – Twelfth
    Oct 4, 2014 at 0:43
  • $\begingroup$ And to add to Jon's point, the rockies will trap the vast majority of ash that would be sent west meaning cali is unlikely to get much if any ash unless it is high enough that its going to pervade the entire planet. $\endgroup$
    – Chad
    Oct 8, 2014 at 14:00
  • 2
    $\begingroup$ Welcome to The United State of Florida! $\endgroup$ Nov 26, 2014 at 15:17

4 Answers 4


Don't get quite so carried away, now. There would not be world-wide earthquakes, and probably not even extinctions (there weren't last time), and really only north America would be severely affected, while the rest of the world experienced a year or so of cooler temperatures. Caldera eruptions are now not considered extinction-level events, though they would certainly have deleterious effects on human civilization in the surrounding areas.

Humanity would certainly survive, though there would be a large number of deaths in north America. Plants would start to reappear in the ash-covered landscape within ten years, or more rapidly if humans assisted matters.

See http://www.livescience.com/20714-yellowstone-supervolcano-eruption.html for more information.

  • $\begingroup$ Is it conceivable that the eruption could cause some sort of chain effect that would trigger other eruptions? I admit that I've only done some Wikipedia research on the subject. $\endgroup$
    – majortopio
    Oct 3, 2014 at 15:11
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    $\begingroup$ A caldera volcano is literally a chain-reaction set of volcanoes. First one erupts, and the stresses of the eruption cause a fault that allows another to erupt beside the first, and so-on around the edge of the magma chamber, leading to the roof of the magma chamber collapsing and forcing the magma out through the volcanoes around it. $\endgroup$
    – Monty Wild
    Oct 3, 2014 at 17:24

Having gone to school in the Pacific Northwest, with a teacher who very much loved rocks, this was actually something we covered in class with documentaries, etc.

What are the largest geographical implications? Yellowstone would flood a very large area in lava rather quickly creating some lovely plains. The earthquake would probably trigger our San Adreas fault which would set off pretty much every fault in California as well as causing the Juan de Fuca Plate to subduct. The resulting quake would have three major effects and possibly a fourth. The first would be that it would probably set off volcanoes in the Ring of Fire (not immediately but as seen on a time lapse of recorded volcanic eruptions would look pretty instantaneous). The second would be the strength of the earthquake makes it behave completely differently than normal and "earthquake-proof" structures would receive much more extensive damage than regular wooden houses, large towers would be gone. The strong quake would induce liquefaction in extensive areas west of the Rocky Mountains so places like Puyallup would disappear underground and events like the Oso mudslide would happen in many areas. Third, the tsunami generated would be massive and at least 80 ft high, probably much higher. The tsunami would come after the earthquake so the structural damage would probably allow the tsunami to collapse any remaining structures. You have typical flooding problems and slightly more drastic tsunami ones around the entire Pacific. The fourth is it could trigger Rainer which would be much worse. Also Mt. St. Helens if its re-pressurized enough and the eruption of Rainier doesn't effect it. If it did trigger it would be quicker than the Ring of Fire. Any hope of anyone surviving west of the Rocky Mountains probably just completely disappeared. Ash levels would significantly increase especially in our bread-basket states.

Would humanity would survive such an event? At least some of humanity would survive pretty much anything that could be dished out from such an event, especially around the Atlantic. The different regions would be affected separately and at different times and we know enough to be able to have at least a small group dodge most of it.

Extent of damage to nature both in the ash-covered areas and the surrounding landscape? How long would/could it take for the winter to lapse? I don't remember enough about the expected ash levels to say. It definitely would release a decent amount of particulates into the air, but going off any other high-ash events I could think of we'd be fine (the world won't turn into Pompeii and it would certainly effect temperature but I don't think we'd get too cold).

Does it get worse? You didn't ask about non-geographical but its probably worth mentioning that a large part of the global economy is centered around the Pacific, that the US provides a lot of the foreign aid in terms of disaster relief, and that we would have a large drop in US food production. You would probably see the worst global depression unless the death-toll offset the gross losses in production, neither being a great scenario. Also you should probably count the number of nuclear reactors and radioactive dump sites around the Pacific Rim and add them all to the "apocalypse-level" around the Pacific.

Note: The chain reaction is an extremely likely scenario if Rainier were to go off first. Please note that the chances are lower for the chain if other things go off first. The lowest chances probably occur with Yellowstone erupting first, but its still a possible scenario.

  • $\begingroup$ On the reactor bit. Remember how people reacted to just one breaking: Fukushima $\endgroup$
    – Black
    Nov 2, 2018 at 6:01

Are you aware of the Toba extinction event? Early in human history, an Indonesian volcano called 'Toba' erupted (70k years ago)...it's a crater lake now. The resulting fallout saw humanity reduced to no more than a couple tribes in Northeastern Africa and all of current humanity descended from that. Using ice cores from Greenland, it is possible that this eruption kicked off a 1000 year cooling event for Earth and dropped life to only the most capable of hanging on.

This is the eruption event you are thinking of...Yellowstone is not that. As Monty points out well, Yellowstone is a caldera eruption and not the same beast. It'd still suck to live anywhere near Wyoming had it happened, but definitely not an extinction event.

  • $\begingroup$ Yes, that is the event that I'm basing this off of. I was not aware that there was such a large difference between the types of volcanoes. $\endgroup$
    – majortopio
    Oct 3, 2014 at 22:19
  • $\begingroup$ Two very separate volcanoes to consider then. Kilauea is an active caldera volcano on Hawaii...it basically bubbles over with lava from time to time releasing relatively slow moving lava out and towards the ocean. THe other far more explosive kinda is like mount st.Helens (which blew sidways limiting what made it to the upp atmosphere) or more recently Icelands bardarbunga eruption (considerably smaller, but same explosive idea) $\endgroup$
    – Twelfth
    Oct 3, 2014 at 22:48
  • $\begingroup$ Yes but 70KY back tribes were stone age. Neanderthals in Europe survived OK. Dangers to today's society with all technologies available would manageable. But for more oomph you can add few huge meteor strikes causing devastating floods and tsunami everywhere except Tibet and Andes, and massive solar flare. Now we are talking business. And does not have to happen same week. $\endgroup$ Oct 30, 2014 at 0:57

Α scientific group proposed already in world congresses a magma mitigation plan! http://www.global-providence.info/
Based on diversion of magma stimulating cosmic rays' electricity, as we do with spacecrafts and satellites: "Explosive volcanic eruptions triggered by cosmic rays: Volcano as a bubble chamber" - Ebisuzaki, et al sciencedirect.com/science/article/pii/S1342937X10001966


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