Related: Could a Dwarven Civilization Exist?

Background: A Dungeons and Dragons world (for all intents and purposes, Tolkein lore is close enough) in which a group of colonists far from home are building a new city. The Dwarves find a volcano and see it as an opportunity to build a city to rival their homeland. They are currently 25 strong, plus 50 colonists of other races (elves, gnomes & humans), with hundreds more on the way. They have only a handful of mages.

Note that I know that this is realistically a horrible idea and everyone would die on day 1, but this is fantasy, so I'd like to be as believable as possible with my handwaving.

Benefits of this plan:

  • Valuable materials. Lots of unobtanium in them hills!
  • Natural defenses. No need to build walls, let the mountain keep out attackers.
  • Magma smithing. With sufficient protection and Dwarven engineering, lava smiths could invent otherwise impossible crafts!
  • It's cool! Seriously, for a group of people obsessed with reputation and legacy, how awesome would it be if you were the first dwarves to live in a volcano? Think of how fearsome everyone would think you are.

Hurdles to Overcome:

  • Ridiculous heat. Partially mitigated by dwarven resiliance but still a problem. Is wall shielding a possibility?
  • Toxic fumes, especially sulfur. Miners in real life dealt with some nasty gases, can I use the same techniques?
  • Lack of food. This is a factor in regular dwarven cities so I can hand-wave "mushrooms and deep dwelling creatures"
  • Regular and violent tremors. Is good structural construction enough?
  • Lava flows/pools. Would be nasty to break into something like that, though it feels like it would be obvious if you are approaching.
  • Eruptions. Kind of a culmination of all of these problems dialed to 11.

What are the possible solutions for the obvious hurdles presented by living in an active volcano? What are the potential benefits? Are there prominent examples from high fantasy media to draw inspiration from?

Edit: Regarding volcano type, it is a shield volcano that is part of a larger, non volcanic mountain chain mostly inspired by the Rockies. It is inland, about 50km from the ocean coast. It is an active volcano, that erupted a few weeks prior to the colonists arriving.

  • 1
    $\begingroup$ Welcome to the site. Can I organize / format the question a bit so it's clearer? Interesting idea too. $\endgroup$
    – Zxyrra
    Commented Feb 8, 2017 at 2:52
  • $\begingroup$ @Zxyrra Please do. I'm fumbling with mobile, I would appreciate that. And thank you! $\endgroup$
    – Alex F
    Commented Feb 8, 2017 at 2:54
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    $\begingroup$ yes clarifying the type of volcano will make a difference, A volcano like yellowstone might work better, no lava but lots of magma and hot springs, which could be used to power machines. these volcanoes also tend to produce very fertile soils. $\endgroup$
    – John
    Commented Feb 8, 2017 at 6:03
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    $\begingroup$ A sheild volcano would be more stable active laval eruptions don't build up much pressure but strato can vary widely depending on how much continental crust they had to burn through to form, if it is something like the rockies and not like Japan then the volcano is going to have the temperament of a toddler on pcp. $\endgroup$
    – John
    Commented Feb 8, 2017 at 15:11
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    $\begingroup$ Ash eruptions are powerful, explosive, hard to predict and impossible to steer. lava eruptions are fairly easy to predict and can be easily mitigated with channels and basins. Now thats not saying strato can't be stable. basically the more often it erupts the less problematic it will be. if you want strato model it on Mount Etna and it should be mostly good, you will always have issues with weakening the volcano, lava based volcano will be the most structurally sound. $\endgroup$
    – John
    Commented Feb 8, 2017 at 15:20

5 Answers 5


Solutions to hurdles

  • Stay toward the outside. While it's unclear exactly how hot the solid rock inside volcanos is, one source says it's an efficient insulator - meaning you may be okay. If worse comes to worst, don't dig so deep toward the lava chamber, and expand straight downward instead. Unfortunately, you can't actually build into the lava chamber itself - it's way too hot.
  • Fumes aren't a huge problem. They are most abundant toward the actual magma / lava itself, where the temperatures are way beyond reasonable to live. While outside, the best you can do is a fabric or linen facial covering for any ash present. Volatile gases are beyond your control, but they probably won't bother you often.
  • Import food or grow outside. Underground caverns aren't a great place to grow crops, and unless dwarves have an effective way to terraform caverns, I would recommend having fields on the slopes of the volcano. Ash is actually a fairly nice fertilizer, too, so terraced farms should be effective.

Image from http://weshareinterests.com/?p=876 https://homesteading.com/terrace-farming/

  • Build smaller caverns. Tremors are inevitable. While most rooms should remain structurally sound, you don't want to risk a rain of heavy rocks that become dislodged from a larger roof. Consider smaller rooms with columns, or hang the walkways you plan to use from the ceiling to help absorb some of the shock.
  • You will not accidentally tunnel into magma. Temperature increases substantially as you reach it.
  • Eruptions are inevitable, so be prepared. Dig channels in the mountain slope early on to reroute any magma that flows down as much as possible. Use multiple tunnels and multiple entrances / exits so that even when many are blocked, there will always be a way out. Include some longer tunnels running miles away, even - they may be your last hope of escape if the surface is volatile. Also have a way to firmly shut every door into and out of the compound - preferably with heavy stone - to prevent magma, ash, and gas from entering. Finally, use similar precautions for your air ducts - multiple vents that are easy to close and resistant to magma and corrosion. You don't want to suffocate by closing everything off.


  • People will be afraid of imminent death when they go to attack you
  • Magma can be rerouted from atop the volcano, through man-made tubes, into your blacksmith's shops.
  • Volcanoes are rich in rare gemstones, which are often carried up with magma!
  • Obsidian, a volcanic rock, makes very strong tools and weapons
  • 4
    $\begingroup$ Unintentional added benefit: a "the dwarves dug to deep" storyline! $\endgroup$
    – Alex F
    Commented Feb 8, 2017 at 3:47
  • $\begingroup$ @AlexF Indeed., $\endgroup$
    – Zxyrra
    Commented Feb 8, 2017 at 3:48
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    $\begingroup$ Obsidian actually wears down its edge relatively quickly. it is more of a volcanic glass then a tough material so any tools made from it requires far more support then a metal tool/weapon. One of the benefits of obsidian however is that any tools made from it will be extremely sharp. $\endgroup$
    – Hannah
    Commented Feb 8, 2017 at 14:26
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    $\begingroup$ You're not going to have obsidian from any volcano you could survive the eruption of, obsidian comes from Rhyolite volcanoes, which form very large holes in the ground when they erupt, see Lake Taupo, otherwise very comprehensive. $\endgroup$
    – Ash
    Commented Sep 25, 2017 at 17:11

There is a game called Dwarf Fortress that make you take care of a lot of this issues.

  • Lack of food Volcanic soil is very good for crops, so, if the city is not reclusive they can farm fields on the surface and keep the most nutritive mushrooms inside the city.

  • Intense heat If the city is built too deep with no heat source they will freeze to death, deploy some pipes along the city to forward hot gas, melted rocks or other stuff to keep them warm.

  • Intense heat Efficient cooling system. You could use some pipes with water and/or if they have plenty of resources a good cooling mechanism wold be to dissipate heat with fans (fed by the electric central) and metal dissipators, so you save some water for other purposes.

  • Energy Find a water source and you can build a steam powered electric central to develop high technology.

  • Keep them happy I know they are dwarves, but they have feelings right? With no natural light a lot of mammals tend to develop depression and/or aggressive behaviour. What about some big chandeliers on public spaces made of natural magma waterfalls. A few more between halls and lets say schools and workshops. Don't let your dwarves' hearts become evil.

  • Earthquakes and toxic fumes In such a dangerous place there is no place for personal appeal in matter of shelter. Every family should live in almost identical houses and designed areas, which would lead to a very efficient emergency/disaster protocol to evacuate the city and save the population.

  • $\begingroup$ The energy part is clever! +1 $\endgroup$
    – Zxyrra
    Commented Feb 8, 2017 at 3:48
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    $\begingroup$ One of your statements is actually wrong. The deeper you go the hotter it becomes. $\endgroup$
    – r41n
    Commented Feb 8, 2017 at 13:53
  • $\begingroup$ You are right, lets exchange the heating for a cooling mechanism, they need a lot of metal (like aluminum) and fans to disepate the heat. $\endgroup$
    – UrielUVD
    Commented Feb 8, 2017 at 20:11
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    $\begingroup$ Bonus points if housing is layed out in nice patterns: goo.gl/images/akP7FB ;-) $\endgroup$
    – fho
    Commented Feb 8, 2017 at 20:31
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    $\begingroup$ +1 for mentioning Dwarf Fortress, that was my first thought on seeing the question. $\endgroup$ Commented Apr 4, 2017 at 11:07

If the lava smiths and engineers are channeling the volcano's heat and magma for various purposes, that could (at least in theory) relieve some of the pressure. This would reduce the chance of a new eruption.

You say it erupted recently, so it would probably be dormant for a while post-eruption anyway.


Recently dormant or barely-active volcanoes are a better way to go.

A recently dormant or barely-active volcano gives most of the benefits (usable warmth, power source, recently crystalized gems and jewels) and avoids many of the problems (eruptions, earthquakes, magma, poisonous gasses.)

The rub is that there are other underground-living/lairing species that also like just-barely-warm volcanos as their homes. And some of those aren't exactly into sharing...

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    $\begingroup$ But those species would make great food ;) $\endgroup$
    – user31746
    Commented Feb 8, 2017 at 13:43

I am not good with this but here is a suggestion:
Hurdle 1: Stone walls won't work, as once, in a medieval book, a fire burned so fiercely some stones in a stone wall cracked. This is that heat x500. Try something more fireproof, with some water. There should be a magma chamber holding magma, stay away at all costs, and make your city at the base. Is it underground though? Find some natural cooling things. Try hauling a lot of water there, then let it evaporate, which will cool you. Hurdle 2: Maybe somehow get wind in there, but this is a hard one for me.
Hurdle 3: Mushrooms, and things that hold well in heat.
Hurdle 4: We have made buildings strong enough to withstand strong earthquakes. Try using that concept.
Hurdle 5: Maybe a squad with buckets? Otherwise strong walls. Euptions: Choose a non-active or not as active volcano.
However: What type of volcano? This has been mentioned in a comment already. Is the volcano more flat, does it have an open top like science fair volcanoes, or does it have rock covering the top like a mountain? Please clarify!

  • $\begingroup$ The question has been updated $\endgroup$
    – Alex F
    Commented Feb 8, 2017 at 3:43

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