A massive earthquake in D&D - Any advice?

[Jon_Dahl]

I'm planning to have a truly massive earthquake in my game, or perhaps a medium one. At the moment, I'm thinking something along the lines of Shaanxi earthquake, which killed nearly a million people. The earthquake will mostly be centered on a prosperous and (too!!) stable kingdom (1.8 million people) and the neighboring kingdoms are a bit smaller. Large population centers exist.

I was thinking about having the earthquake just when some NPC is going to say something important.

How should this work? We have forest fires and quicksand in SRD, but no earthquakes.

[Keltest]

Maybe not natural earthquakes, but definitely magical ones.

http://www.d20srd.org/srd/spells/earthquake.htm

You probably wouldn't get the fissure effect particularly often (though what do I know? I live in Pennsylvania) in the middle of a city, and obviously the area would be altered to whatever you need it to be, but it seems to be a good foundation for what you want to do.

[Ashtagon]

I've actually lived through multiple earthquakes, although the strongest was about magnitude 5, which is still fairly petty. This one was my most memorable.

Most of the effects of the earthquake spell are highly cinematic, and do not happen in real earthquakes, even real powerful ones. Especially the fissures. I think we have one of the early superman films to thank for that.

So I guess the first question is, are you looking for realistic effects or something obviously supernatural/surreal?

[Keltest]

I've actually lived through multiple earthquakes, although the strongest was about magnitude 5, which is still fairly petty. This one was my most memorable.

Most of the effects of the earthquake spell are highly cinematic, and do not happen in real earthquakes, even real powerful ones. Especially the fissures. I think we have one of the early superman films to thank for that.

So I guess the first question is, are you looking for realistic effects or something obviously supernatural/surreal?

I mean, the fissures are obviously magical, and are made so that the spell is useful when there isn't anything to drop on somebody.

[Jon_Dahl]

I've actually lived through multiple earthquakes, although the strongest was about magnitude 5, which is still fairly petty. This one was my most memorable.

Most of the effects of the earthquake spell are highly cinematic, and do not happen in real earthquakes, even real powerful ones. Especially the fissures. I think we have one of the early superman films to thank for that.

So I guess the first question is, are you looking for realistic effects or something obviously supernatural/surreal?

Something that would fit the D&D natural disaster scheme pretty well. We already have examples.

[Ashtagon]

• Cave, Cavern, or Tunnel: Seems realistic enough.
• Cliffs: Areas with enough seismic activity to matter will either form cliffs strong enough to withstand an earthquake or will not have cliffs. This effect can happen, but only in 1000-year events at most.
• Open Ground: Fissures lol.
• Structure: Seems reasonable enough.
• River, Lake, or Marsh: Yeah, that draining thing doesn't happen.

Realistically, the actual quake can last up to a few minutes, possibly with multiple aftershocks. During the quake, you're probably going to be knocked over, and movement will be reduced if possible at all, depending on quake severity.

Landslides are possible. Check Mountain Terrain in the SRD for details.

Fires from earthquakes are mostly a modern thing, from damage to electricity and gas connections. The average pseudo-mediaeval city won't have this risk, except in districts with highly specialised industries.

Soil liquefaction from earthquakes is a real thing. The vibrations turn the normally-solid surface into a liquid in practical terms (it behaves as a shear-thinning fluid, a bit like ketchup in a bottle when you slap the bottom). This can take the rock to mud spell description for inspiration, but it only happens on soil (and generally only on aerated soil deep enough to support significant plant life). We don't tend to notice this so much in modern times because most people life quite a way aways from aerated soil.

Near coasts, tidal waves and subsequent flooding are a real possibility, especially if the quake's epicentre is underwater. There's probably a spell in Stormwrack for this effect.

Something akin to fissures can and does happen in real earthquakes (image), but they don't grind shut afterwards. In game terms, you're looking at instantly-created dense rubble, berms, scree, and/or trench terrain features (see the Wilderness section of the SRD).

Buildings fall down. People inside them may get trapped, and stuff can fall on anyone in a building or even just next to one.

That's a guide to what should, realistically, happen. How intense each effect will be depends on the strength of the quake.

Or just treat it as an epic level earthquake spell. That can be fun too.

[Inevitability]

Well, anything that isn't well-built or magically reinforced will probably collapse. That's one of the reasons why the Haiti earthquake was so destructive: it occured in an area with many poorly-built infrastructure.

[Belzyk]

Just remember that that massive amount of death all at once could very well cause the birth of a dark God or artifact

[Telonius]

The Shackled City adventure path has a similar event,

Spoiler

Show

... though caused by volcanic eruption, not earthquake specifically ...

You might find some good ideas for "rescue the citizens" tasks in that chapter.

[Inevitability]

Just remember that that massive amount of death all at once could very well cause the birth of a dark God or artifact

Don't forget good old Atropus.

[MesiDoomstalker]

Well, I think the main thing you need to look at are if the quake is natural (in whats passes for 'natural' in a D&D world) or magical. If its natural, you need to determine it's rating on the Richter Scale and then you have a good approximation on what kind of damage it will do. Then you just need to determine the predominate architecture of the affected area and you can see what kind of devastation it wrought on the cities. You also need to determine the type of terrain and biome in the area. The specifics will determine what a big earthquake does to natural environs.

[Belzyk]

Don't forget good old Atropus.

Oh yeahhhhh I forgot about that douchey elder evil wanna be. Yeah that much death will also bring the deathmoon to your world prolly.

[Coidzor]

If they don't have building techniques which are secure against earthquakes, then many, many buildings will collapse, fall over, or be significantly damaged from peasant homes made of wattle and daub to trappers' lodges made of hewn logs to the fortresses that control the main entrances and exits to the kingdom.

Though the entirety of fortifications are probably not going to all collapse or be rendered into difficult terrain or be trivial to bypass, it's still going to make them less defensible, especially when food stores are ruined by the earthquake and logistics comes into play.

Grain stores might be completely inaccessible until rubble is cleared or have a more insidious bit of minor damage that exposes the grain to too much moisture.

If most structures are single story and mud or adobe with maybe wooden roofs, then casualties from the earthquake itself would be fairly low, iirc, the chaos created afterward and the exposure from lack of adequate shelter would be the real killer.

So, yeah, anything that wants to invade has a fair window of time in which to do so, especially if the army gets redirected to relief efforts.

Significant magical aid will make the cleanup a lot faster, though.

If they do have earthquakes and take them into account in how they build, then temples, fortifications, and important governmental edifices and other similarly expensive buildings are going to hold up well enough to at least not collapse unless you're going crazy extreme. Granaries made by the wealthy or government would similarly be built sturdier if earthquakes are a going concern.

Wizards' towers are probably going to involve walls of force in the foundations, so I'm going to guess that makes them immune to earthquakes themselves.

[DrMartin]

It you want this event to really change the face of your setting, you may find some inspiration in the event book from Malhavoc Press when the sky falls. It describes several sorts of events that follow the fall of a meteorite, that brings with it world-changing consequences. New forms of magic are born, new gods, new monsters, you get the picture.

Obviously meteorite =/= earthquake so if you find something that you like it will require some adapting and refluffing, but it remains an excellent book, definitely worth a read. Also its predecessor Requiem for a God it's in my opinion a fantastic source of inspiration.