Europe, too, is sitting on a giant supervolcano...

[Simon_Jester]

Uh... you do remember the bit where this is a hysterical Daily Mail article?

I mean yes, disaster planning is all well and good, but seriously, "destroy all life on the continent?" Supervolcanoes don't do that, if they did there wouldn't be any life anywhere in the world, because we get supervolcano eruptions every few tens of thousands of years.

[someone_else]

Isn't this kinda old news yes?

I mean yes, disaster planning is all well and good, but seriously, "destroy all life on the continent?"

Well, all meaningful lifeforms anyway.

It would surely manage to pull off a Day After Tomorrow on Europe.

[Alyrium Denryle]

Isn't this kinda old news yes?

I mean yes, disaster planning is all well and good, but seriously, "destroy all life on the continent?"

Well, all meaningful lifeforms anyway.

It would surely manage to pull off a Day After Tomorrow on Europe.

That depends on the prevailing winds. The mediterranean basin is well and truly fucked due to megatsunami. However, the ash cloud my not cross over the continent proper (it depends on the season whether it will do that or not. In the summer, they probably wont. Winter... probably will). There will be a few years without a summer due to sulfur dioxide in the atmosphere increasing the earth's alibido effect, but that will be global and it wont wipe out life. Just make it highly unpleasant.

[The Vortex Empire]

Out of curiosity, how would North America be affected by this supervolcano if it were to go off?

[El Moose Monstero]

CAVEAT - This is written on the fly before dinner, there may be some errors and some severe oversimplifcations which a more geophysical volcanologist could answer better or more accurately.

For Maddoctor:

I can’t speak to any solutions involving sonication or otherwise. I’m happy to answer questions and outline some of the issues, but it seems that even before you get to figuring out what to do with a magma chamber and how you might stop or limit an eruption, you’ve got to get to grips with the problem of how to get to the magma chamber and the scale on which you’d need to do it. These things along put this discussion so far into the realms of science fiction (IMO) that you’d have to question whether a society capable of negating an eruption couldn’t find something better to do or could just clear up the mess afterwards rather than trying for prevention.

Anyway, with respect to your questions about volatiles and bubbles:

This may be a bit hazy and likely horrendously simplified as I’ve been working at the other end of eruptions for a while and haven’t looked at this stuff in ages or in any great detail. Gases are dissolved chemically in the silicate melt, usually associated with interstitial cations within the network, or in the case of sulphur, with iron. Anyway, as a general rule, the less silica you have in something, the more gas can be dissolved (i.e. bonded into the silicate network in association with the other cations). Dropping the temperature leads to crystallisation and solidification of the silicate network (Tg is glass transition, i.e. transition from fluid melt to frozen glass structure), which preferentially partitions the non silica components into crystals, enriching the remaining silicate melt in silica, decreasing gas solubility, forcing it to form bubbles or to diffuse through the melt until it can form bubbles (i.e. as a result of a concentration gradient forming at the melt surface). Thus, you get pressurisation of bubbles as you cool, up to a point. For some horrendously complex reason, something to do with strain rates I think, once you get above 55% crystallinity, it’s impossible for the magma to erupt any more. The addition of extra melt injected from below there is problematic as that adds more gas into the mix (as volatiles will diffuse into the upper melt) and increases the pressure, and can also drop the crystallinity by introducing new heat and melting – potentially turning an uneruptable magma back into an eruptable one again. It doesn’t have to involve cooling, the addition of fresh magma and volatiles is a more usual reason for initiations of eruptions.

As an aside, if you cool magma on the surface (i.e. obsidian), you can freeze the structure of the glass as it was – i.e. you can preserve the volatiles dissolved within the melt. That’s fine until you heat it back up, when the structure relaxes as bubbles can form again, so even if you did find a way to magically freeze the structure of the magma, you’d be leaving a ticking time bomb for future generations, albeit generations hundreds of thousands of years down the line.

As an additional aside, eruptions themselves obviously don’t tend to start in the magma chamber (with some possible exceptions), but in the conduit above. Eruptable magma ascends, bubbles form, constraining lithospheric pressure drops so they want to expand but (in the case of a silicic eruption) are constrained by the viscous melt walls. In fluid (basaltic) systems, gas bubble escape is easier which is why you don’t tend to get big explosive eruptions fed by basaltic magmas (although there are some exceptions e.g. Hekla, Iceland). As the magma rises, gas bubble internal pressure increases until eventually it overcomes the constraining pressure above it and breaks, shattering the surrounding walls and releasing the gas. This releases the pressure on the magma below, so the same thing happens there, and you get a fragmentation wave starting which propagates into the rising magma. This usually happens somewhere between 500-2000m below the surface, and the resulting jet of gas and magma fragments accelerates to the surface, breaching it and giving you the visible eruption.

With respect to anything more detailed on magma chamber stuff, I’m honestly at the edge of my to-hand knowledge here without going off and finding books, and I don’t think I’d ever be able to answer any more detailed questions about how to negate a magma chamber’s eruptions potential without basically talking out of my ass.


Re: supervolcanic effects

As pointed out, Daily Mail, hype, etc, so I’m talking here purely on a RAR hipotheticle!!11 discussion point of view rather than supporting any hysteria about the dangers of supervolcanoes.

Ignoring the tsunami effects, which AD has covered and I don’t know much about that stuff, just playing to my area here.

I doubt this volcano would be an end of meaningful life – the last eruption was 200 km3 of magma I think, which is a lot, but it’s not technically a super-eruption, rather an ultra-plinian, if I recall.

Assuming that your SO2 output is about 0.1% of erupted mass, which I think is a general ball park figure, you’re talking 500 Mt of SO2, which may be an overestimate, it depends on a lot of things. Anyway, in that case, you’re talking about a probable initial global cooling effect of 4-5 degrees IIRC sustained for a few years, then a few decades to return to pre-eruption norms. What effect you get from that is debatable, but general fucking over of agriculture is likely, change in extent of winter snow cover, changes in atmospheric circulation and weather patterns are all probable outcomes. However, even in areas where agriculture might not be so strongly effected, knock-on effects as a result of more afflicted regions are going to be major. As we saw with Iceland, the true impact of any eruption is not just confined to the effects on the immediate environment, but on the global human network, which is clearly a bit on the fragile side, so I imagine that even a more moderate eruption impacting Europe would have a lot of social and economic repercussions beyond the purely scientific. Farmers in Kenya lost their livelihoods when the expensive orchids they exported to Europe were grounded and had to be destroyed when the ash cloud grounded flights, for example, even though no physical aspect of the eruption ever touched them.

In terms of effects of the widespread ashfall, I might come back to those if there’s sufficient interest, but this is enough of an essay right now, and frankly there’s an assload of different things to talk about, but only on a pretty damn qualitative basis.

[Sky Captain]

I doubt this volcano would be an end of meaningful life – the last eruption was 200 km3 of magma I think, which is a lot, but it’s not technically a super-eruption, rather an ultra-plinian, if I recall.

That would be similar to Tambora eruption in 1816. Although not an end for all life in Europe, but still a disaster far bigger than anything our modern society has ever faced with potential to kill millions and wreck entire countries.

Regarding agriculture is it true that our modern crops are much less tolerant to bad weather because they are optimized to give as much yield as possible than crops grown when Tambora blew? I have heard this claim several times and it would be nice if someone with more knowledge about biology could explain it.

[Irbis]

In terms of effects of the widespread ashfall, I might come back to those if there’s sufficient interest, but this is enough of an essay right now, and frankly there’s an assload of different things to talk about, but only on a pretty damn qualitative basis.

Yes, please, even a brief would be appreciated.

No. It is still mad.

On the contrary, dear Sir, if anything, it's not mad enough

[madd0ct0r]

Thinking over this a little more, whilst in the shower, I remembered the mechanisim for debubbling concrete is as follows:

vibrate at high frequency. watch bubbles come out.

But what's actually happening is the vibrations are sending little waves through the liquid concrete. When they hit the fine sand particles resonance gets the sand shaking, which is what throws the air bubbles out.

Is there an equivalent fine particle in magma? I seem to recall it's properties being compared to thick yoghurt. So it'd be a case of degassing yoghurt. um. anyone got any experience of this?

[Alyrium Denryle]

Thinking over this a little more, whilst in the shower, I remembered the mechanisim for debubbling concrete is as follows:

vibrate at high frequency. watch bubbles come out.

But what's actually happening is the vibrations are sending little waves through the liquid concrete. When they hit the fine sand particles resonance gets the sand shaking, which is what throws the air bubbles out.

Is there an equivalent fine particle in magma? I seem to recall it's properties being compared to thick yoghurt. So it'd be a case of degassing yoghurt. um. anyone got any experience of this?

No. The gasses are dissolved due to high pressure. As the magma rises, they are able to escape. However, in low viscosity magma, the magma is more liquid, so as it rises, the gas can escape harmlessly gas coming out of solution can rise and escape harmlessly (well, not harmlessly. It is still stuff like sulfur dioxide). Think of it like flattening pepsi by just letting it sit open. More viscous magma does not allow said bubbles to escape, so when the magma comes out, all the gas escapes at once and the magma explodes in a very angry super-heated froth. Like shaking a pepsi bottle and then opening it.

[Isolder74]

On the subject of Yellowstone, this is a few maps of the areas covered by previous eruption of that super-volcano.



Notice the fact Mount Saint Helens looks like a pop gun in comparison. Actually this map show the US has two super-volcanoes to worry about.



In the immediate aftermath of a eruption everything in the grayed out areas would be more or less done for. There would be a massive drop in global temperatures and the next few decades would be a mess.

[El Moose Monstero]

snip

Is there an equivalent fine particle in magma? I seem to recall it's properties being compared to thick yoghurt. So it'd be a case of degassing yoghurt. um. anyone got any experience of this?

snip

In addition, if all magma had the viscosity of thick yoghurt, we'd be laughing. I've not got the viscosity of thick yoghurt to hand, but wiki says that the viscosity of ketchup will be <10^2 Pa s. I don't know much about concrete, but a google says 10^2-10^3 Pa s for wet concrete, is that about right or am I using the wrong data or term?

Anyway, as a fundamental point, at eruption temperatures, basaltic magmas can indeed get to the sort of thick yoghurt viscosities. However, at the eruption temperatures of silicic magmas, viscosities are much higher. The most silicic (rhyolite) at 800C is 10^10 Pa s, and even the next composition "up" from basalt (andesite) is 10^4, so we really are talking about a very different system where degassing will simply not occur. I was working with silicic rocks a couple of weeks back, taking them back up to magma so we could make volcanic glass out of them. Eruption temperature for silicic magma is normally 700-900C, but in order to get the volatiles out of the glass on a fast timescale (hours to days), we had to go to 1400-1700C.

[madd0ct0r]

So in order to degass the magma, we have to make it hotter. oh boy. mad science just got madder.

[Broomstick]

This thread sort of reminds of when the news about the Yellowstone supervolcano hit North America. A certain number of people ran around yelling "What can we do? What can we DO?".

Answer: Pretty much nothing.

Sure, speculate all you want, but really, there's about jackshit we can do about these things. Certainly we shouldn't start with manipulation of magma chambers with the really big guys, there are plenty of small volcanoes to play around with where, if we pop it like a zit, the consequences won't be nearly so dire. Actually, though, the art and tech of volcano degassing is all speculation at this point, if not outright science fiction.

There ain't shit we can do about these right now.

Disaster planning? Well, depends where you are - clearly if this one goes off Naples is totally fucked non-existent. The Mediterranean basin is fucked. As noted, wind patterns will make a significant difference as to immediate impact. Globally, there are likely to be food shortages, certainly major disruptions everywhere. Extremely unpleasant even for those halfway around the planet due to knock-on effects in weather and economics.

In a sense, a super-eruption is worse than a major asteroid strike as we have SOME chance of seeing an asteroid coming towards us, giving us some warning (which may or may not do any good whatsoever). As no one has ever seen a supereruption we don't know what proceeds them, we can only guess. We likely won't have any real warning. Even if we did, there is no way to evacuate the danger zone.

So, like asteroid strikes, I've just decided not to worry about something I can't do anything about.

Not that that stops me from joining in the speculation sometimes.

[The Duchess of Zeon]

Removing the amount of energy liberated in the Yellowstone Super Caldera would actually be disturbingly easy if we were using it to generate 50% of the United State's electrical power; it would supply that energy need for 70 years (the energy of one supercaldera eruption event). The problem is, as Alyrium noted, that the caldera does not exist in a vacuum. Sure we could spend like 10 trillion dollars (I think my estimate for the project was about 7 trillion when I talked with Skimmer) and literally use up the same amount of energy the eruption would liberate, but the question is if that would do anything. The question can only be answered by how fast energy can be added into the system, and when there is an equilibrium established. Establishing the equilibrium might actually be possible; in the 1970s this sort of thing was proposed as a future clean energy source and shows up in references in science fiction as a "core tap" usually. It would, however, be the equivalent in terms of engineering challenge of, oh, say, a project to build the Three Gorges Dam... On the moon.

Could this be done as part of some kind of New Deal and could it yield measurable safety benefits? The answers are yes and unknown; but it's quite politically impossible regardless.

[Sarevok]

^^

Assuming the money is available are there any dangers from such a project ? Are "core taps" relatively safe to build ?