# If/When Vesuvius Erupts Again, Is Naples Screwed? Is Tokyo Screwed When Fuji Erupts Again? **URL:** \ **Category:** Factual Questions\ **Created:** [July 4, 2022, 9:11pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422 "2022-07-04T21:11:34Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [July 4, 2022, 9:11pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/1 "2022-07-04T21:11:34Z")
It seems we enjoy building major cities near dormant (or active) volcanoes. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [July 4, 2022, 9:26pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/2 "2022-07-04T21:26:34Z")
We also build where there are earthquakes, hurricanes and tornadoes. I don’t think there are many places _not_ subject to disasters or extreme conditions. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [July 4, 2022, 9:28pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/3 "2022-07-04T21:28:09Z")
> [@HeyHomie](#): > > It seems we enjoy building major cities near dormant (or active) volcanoes. Yup, we put the United States near Yellowstone. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 4, 2022, 9:32pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/4 "2022-07-04T21:32:06Z")
When [the Cascadia Subduction Zone lets loose](https://youtu.be/76b_WGzCI54) it is essentially going to take out the entire coastal Pacific Northwest. The next time the New Madrid fault really lets go it’ll likely devastate cities as far away as St. Louis, Nashville, Memphis, and Little Rock. On even a short geological timescale, there are few places on Earth that are really secure. Japan and Italy are so covered with quiescent ‘active’ and presumably dormant but recently (within the last 10,000 years) active volcanos that it would be difficult to build a city that would not potentially be at threat; there is, in fact, a [potentially active volcano in the suburbs of Rome](https://www.scientificamerican.com/article/a-volcano-might-be-brewing-under-rome-s-suburbs/) but nobody is fleeting the city. Stranger ---
**Author:** ![suranyi](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@suranyi](https://boards.straightdope.com/u/suranyi)\ **Post date:** [July 4, 2022, 9:34pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/5 "2022-07-04T21:34:21Z")
Besides what’s already been said, note that the soil around volcanoes is often extremely fertile. So they actually attract people, historically. ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [July 4, 2022, 9:36pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/6 "2022-07-04T21:36:04Z")
Vesuvius is the least of the problem, the whole area is a supervolcano. OK, not the _least_ problem, but things could get orders or magnitude worse than a Pompeii. ---
**Author:** ![Moriarty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moriarty/32/49_2.png) [@Moriarty](https://boards.straightdope.com/u/Moriarty)\ **Post date:** [July 4, 2022, 10:08pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/7 "2022-07-04T22:08:23Z")
> [@Riemann](#): > > we put the United States near Yellowstone. And when that blows, we can say goodbye to the Midwest U.S. [![](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/vhp_img316.png) ](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/vhp_img316.png) ---
**Author:** ![Leaper](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@Leaper](https://boards.straightdope.com/u/Leaper)\ **Post date:** [July 4, 2022, 10:25pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/8 "2022-07-04T22:25:00Z")
I’m not exactly sure what I’m seeing here. I’d thought, given the context, that this was a map of a projected Yellowstone blowup, but the regions are already named, so they’re ash beds from the past? If so, which parts should contribute to the hypothetical? All of it? How do you tell? ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [July 4, 2022, 10:35pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/9 "2022-07-04T22:35:06Z")
We are all screwed tomorrow, when CERN opens up demonic portals to hell. I saw it on Twitter. It’s almost too late for panic buying, but do what you can. At the very least, get $6.66 worth of toilet paper. ---
**Author:** ![APB](https://avatars.discourse-cdn.com/v4/letter/a/8e8cbc/32.png) [@APB](https://boards.straightdope.com/u/APB)\ **Post date:** [July 4, 2022, 10:35pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/10 "2022-07-04T22:35:44Z")
Vesuvius has erupted many times over past two millennia and each time the damage was mostly confined only to the immediate vicinity. The AD79 eruption was unusually large and even then the distribution of the devastation was very uneven. Some areas closer than Pompeii were less damaged. Later eruptions were far smaller. [This map of the eruptions between 1631 and 1832](https://www.historytoday.com/archive/cartography/map-vesuvius-1832) gives a good sense of just how limited the lava flows usually were. None of those eruptions have come close to posing an equivalent threat to central Naples. That’s why the city survived. It’s far enough away that the dangers are mostly the indirect ones. Or rather the centre is still far enough away, as there is the issue of the urban sprawl unwisely close to the volcano. But that’s just one or two suburbs on the outskirts of a vast city. > [@Novelty\_Bobble](#): > > Vesuvius is the least of the problem, the whole area is a supervolcano. > > OK, not the _least_ problem, but things could get orders or magnitude worse than a Pompeii. Yeah, that’s an entirely different matter. But that’s a bit like worrying about the Yellowstone supervolcano. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 4, 2022, 10:41pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/11 "2022-07-04T22:41:24Z")
> [@Riemann](#): > > Yup, we put the United States near Yellowstone. By Yellowstone standards, we also put Europe, Asia, and most of Africa near Yellowstone. ---
**Author:** ![SmartAleq](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smartaleq/32/163_2.png) [@SmartAleq](https://boards.straightdope.com/u/SmartAleq)\ **Post date:** [July 4, 2022, 10:46pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/12 "2022-07-04T22:46:23Z")
Yes, those are historical eruptions of various volcanoes–the Long Valley Caldera blow covered an enormous percentage of the continent when it went off. Still has the possibility of Mammoth Mt getting grumbly again. And there’s no real telling just how bad a possible future blow could be, all we can do is see what happened historically and assume it will likely be of similar magnitude. Might not be, though, because conditions in a subduction zone are always changing, including how much pressure is building up under the volcanoes. The Cascadia fault zone was mentioned upthread and it does have the potential for some amazingly destructive quakes but it also has a couple of spots that historically remove tension from the entire system so it’s possible the giant mega quake might not happen if the lesser fault zones had popped off enough to take the energy potential down. Or it might all go off and zap us all to kingdom come–that’s the fun part about geology, so many variables. The entire earth is a large mobile system that has its own rhythms, stresses and processes that we have absolutely zero control over. There is no place on the globe that is free of all danger and if we’re gonna live here we have to be okay with maybe the planet gets cranky, does a shiver and wipes out big swathes of us. We’re very small, in the cosmic comparison. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [July 4, 2022, 11:29pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/13 "2022-07-04T23:29:25Z")
I visited White Island in 2004. Apparently it’s closed to visitors now. They’ve built several major telescopes atop the big island of Hawaii. As others point out, it’s like hurricanes or earthquakes. They’re still building in New Orleans. ---
**Author:** ![Moriarty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moriarty/32/49_2.png) [@Moriarty](https://boards.straightdope.com/u/Moriarty)\ **Post date:** [July 4, 2022, 11:45pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/14 "2022-07-04T23:45:55Z")
> [@Leaper](#): > > I’d thought, given the context, that this was a map of a projected Yellowstone blowup, but the regions are already named, so they’re ash beds from the past? As already noted, these are previous “blast zones”, to give a flavor of the type of explosion we might expect. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 5, 2022, 3:13am UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/15 "2022-07-05T03:13:13Z")
> [@md-2000](#): > > They’ve built several major telescopes atop the big island of Hawaii. But the people who built them aren’t stupid. Those observatories are on the dormant Mauna Kea, rather than the active Mauna Loa or Kilauea. The hot spot that made the Hawaiian Islands will always be in the far south east of the island chain. So Kilauea is the most active, since it’s in that place; Mauna Loa is less active, it being somewhat futher north and Mauna Kea, being even further north, is pretty much done for. There’s also one off the SE coast that’ll sooner or later take over as most active. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [July 5, 2022, 3:26am UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/16 "2022-07-05T03:26:59Z")
> [@SmartAleq](#): > > The entire earth is a large mobile system that has its own rhythms, stresses and processes that we have absolutely zero control over. There is no place on the globe that is free of all danger and if we’re gonna live here we have to be okay with maybe the planet gets cranky, does a shiver and wipes out big swathes of us. We’re very small, in the cosmic comparison. The better analogy I’ve seen is that the earth is like a big hot bowl of cream of mushroom soup, and the surface crust is like that thin congealed coating on top, pushed around by the convection currents underneath. ---
**Author:** ![Smapti](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smapti/32/17938_2.png) [@Smapti](https://boards.straightdope.com/u/Smapti)\ **Post date:** [July 5, 2022, 3:35am UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/17 "2022-07-05T03:35:21Z")
> [@Stranger\_On\_A\_Train](#): > > When [the Cascadia Subduction Zone lets loose](https://youtu.be/76b_WGzCI54) it is essentially going to take out the entire coastal Pacific Northwest. Maybe we’ll get lucky and Mt. Rainier will erupt first. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [July 5, 2022, 4:35pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/18 "2022-07-05T16:35:52Z")
I take it you’re not around Tacoma or S. Seattle. Mt. Tabor is a supposedly extinct volcano in the middle of the east side of Portland. Been quiet for 300k years maybe. But if goes, it’s taking out some really fine homes. As usual, the east side is always screwed over by the west-siders. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [July 5, 2022, 4:44pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/19 "2022-07-05T16:44:40Z")
Anchorage, Alaska is right across Cook Inlet from Mt. Spurr, Mt. Redoubt, Mt. Iliamna, and Mt. Augustine, all active volcanoes. Every time one of them starts burping, air traffic in the vicinity is shut down. If the wind is right, Anchorage has been covered in a few inches of ash. Further south is Novarupta and Katmai, which was the most cataclysmic eruption in the 20th century, dumping several feet of ash on the nearest town of Kodiak and spreading ash worldwide. That was in 1912, so one can imagine what it would do in today’s world. ---
**Author:** ![Paul\_was\_in\_Saudi](https://avatars.discourse-cdn.com/v4/letter/p/b77776/32.png) [@Paul\_was\_in\_Saudi](https://boards.straightdope.com/u/Paul_was_in_Saudi)\ **Post date:** [July 5, 2022, 9:34pm UTC](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422/20 "2022-07-05T21:34:51Z")
I understand Istanbul is a major earthquake risk. A huge city, with marginal building codes right atop an area of activity. I wonder what the odds are of some huge Biblical-scale seismic happening somewhere in this century. It seems we dodged the bullet pretty well in the last century. [Next page](https://boards.straightdope.com/t/if-when-vesuvius-erupts-again-is-naples-screwed-is-tokyo-screwed-when-fuji-erupts-again/967422.md?page=2)