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Post by the light works on Aug 26, 2014 14:58:48 GMT
for those who missed it - my recent vacation was to Yellowstone park - which is in the caldera of a not-very-extinct supervolcano.
conventional wisdom has it that the next time this volcano erupts, it will obliterate most of the surrounding states - but going through the park left me thinking - magma, on its own, is about as explosive as ketchup. the way a volcano develops explosive force is through a combination of thermal reactions with other material, (I.E. steam eruptions) and through having enough restriction to be able to build up pressure before erupting.
I am not sure it is structurally possible for Yellowstone to have a significantly violent eruption - and the recent history of Mount St. Helens would seem to bear out that premise - it certainly had a major violent eruption that blew half the top off and caused the other half to slide down the Toutle river valley - but after that, the worst it did was launch ash plumes and build little piles of cinders, or lava domes.
any thoughts on the matter?
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Post by GTCGreg on Aug 26, 2014 17:33:44 GMT
Hope you enjoyed your trip to Yellowstone. I haven't been there in about 20 years.
It's my understanding that the magma dome under Yellowstone makes Mt. St. Helen look like a tea kettle in comparison. Super heated magma is like super heated water in a boiler. The only thing keeping it from flashing to vapor is it's being held under pressure. Remove that pressure and you have an instant flash explosion just like when a boiler explodes.
But it's not the magma that would damage the surrounding (like half the country) area. It's all the ash and soot that would be thrown hundreds of thousands of feet into the atmosphere. I've read reports (don't know how accurate they were) that a mega eruption of Yellowstone could dump as much as a foot of ash as far away as Chicago. That says nothing of the months of sunlight that would be blotted out across our country's bread basket.
In any event, if Yellowstone blows, it's going to be major hurting for a lot of people.
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Post by the light works on Aug 26, 2014 18:19:21 GMT
Hope you enjoyed your trip to Yellowstone. I haven't been there in about 20 years. It's my understanding that the magma dome under Yellowstone makes Mt. St. Helen look like a tea kettle in comparison. Super heated magma is like super heated water in a boiler. The only thing keeping it from flashing to vapor is it's being held under pressure. Remove that pressure and you have an instant flash explosion just like when a boiler explodes. But it's not the magma that would damage the surrounding (like half the country) area. It's all the ash and soot that would be thrown hundreds of thousands of feet into the atmosphere. I've read reports (don't know how accurate they were) that a mega eruption of Yellowstone could dump as much as a foot of ash as far away as Chicago. That says nothing of the months of sunlight that would be blotted out across our country's bread basket. In any event, if Yellowstone blows, it's going to be major hurting for a lot of people. I always enjoy Yellowstone. and it was a good trip aside from the 36 hours of driving to get there and back. (which wouldn't be so bad if driving wasn't synonymous with solitude in my household) the caldera is miles across, and the crust is unusually thin (which is why there is so much thermal activity). what I am wondering is whether the physics involved support the likelihood of a catastrophic eruption, I've also read reports like that, and also reports implying that the force of the blast will essentially rototill Montana, Wyoming, and Idaho. what I am wondering is whether you are going to get something like this: or something more like this: |
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Post by GTCGreg on Aug 27, 2014 3:04:14 GMT
The so called "experts" seem to think it's going to be more like the propane tank. Judging by Mt. St. Helen, I think they may be right. Seeing how Yellowstone has a history of erupting about every 800,000 to 1.2 million years or so, and the last eruption was 640,000 years ago. It probably isn't going to blow for at least another 200,000 years or more. Don't think I'm going to lose sleep over it. Maybe this discussion should be in the "needing to vent" thread  |
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Post by the light works on Aug 27, 2014 5:15:19 GMT
The so called "experts" seem to think it's going to be more like the propane tank. Judging by Mt. St. Helen, I think they may be right. Seeing how Yellowstone has a history of erupting about every 800,000 to 1.2 million years or so, and the last eruption was 640,000 years ago. It probably isn't going to blow for at least another 200,000 years or more. Don't think I'm going to lose sleep over it. Maybe this discussion should be in the "needing to vent" thread however, Mt St Helens had the full mountaintop capping it - and providing more back pressure. - and yes, we'll most likely have plenty of warning before it goes. it just left me curious as to what effect NOT having all those cubic miles of rock above the lava would have on the eruption. |
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Post by GTCGreg on Aug 27, 2014 14:31:18 GMT
The eruptable magma at Yellowstone is still between 2.5 and 3 miles beneath the surface. Over that large an area, that's a lot of dirt. I have no idea how deep the magma was under the top of Mt. St. Helen but I doubt it was that deep as the entire mountain is only 8400 feet tall.
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Post by the light works on Aug 27, 2014 15:06:59 GMT
here is a good summary of the events around Mt. St. Helens. www.geology.sdsu.edu/how_volcanoes_work/Sthelens.htmlAccording to it, the thing that allowed the major blast was that the cap that was maintaining the pressure on the magma came off more or less all at once. keep in mind: the yellowstone magma dome is an impressive 18 miles wide - but the caldera is at least 40 miles across. I'm not aware of a volcano that has erupted from a large caldera in that manner, so my curiosity is whether the caldera will prevent an explosive release of pressure by allowing a more diffused release. |
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Post by GTCGreg on Aug 27, 2014 15:26:02 GMT
here is a good summary of the events around Mt. St. Helens. www.geology.sdsu.edu/how_volcanoes_work/Sthelens.htmlAccording to it, the thing that allowed the major blast was that the cap that was maintaining the pressure on the magma came off more or less all at once. keep in mind: the yellowstone magma dome is an impressive 18 miles wide - but the caldera is at least 40 miles across. I'm not aware of a volcano that has erupted from a large caldera in that manner, so my curiosity is whether the caldera will prevent an explosive release of pressure by allowing a more diffused release. For the sake of anyone around when it lets go, I hope that's the case. But I guess past eruptions were pretty violent. At least that's what the videos from 2.1 millions years ago would suggest. |
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Post by the light works on Aug 27, 2014 15:48:06 GMT
here is a good summary of the events around Mt. St. Helens. www.geology.sdsu.edu/how_volcanoes_work/Sthelens.htmlAccording to it, the thing that allowed the major blast was that the cap that was maintaining the pressure on the magma came off more or less all at once. keep in mind: the yellowstone magma dome is an impressive 18 miles wide - but the caldera is at least 40 miles across. I'm not aware of a volcano that has erupted from a large caldera in that manner, so my curiosity is whether the caldera will prevent an explosive release of pressure by allowing a more diffused release. For the sake of anyone around when it lets go, I hope that's the case. But I guess past eruptions were pretty violent. At least that's what the videos from 2.1 millions years ago would suggest. well, I don't think anyone wants to be in the area, regardless... but the thought of scientists assuming a caldera eruption will be the same as a full mountain eruption irritates me. |
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Post by GTCGreg on Aug 28, 2014 1:57:32 GMT
I really don't know enough about volcanos or calderas to know if the scientists are accurate but I have seen enough junk science used as fact in the global warming debate to not trust anyone.
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Post by the light works on Aug 28, 2014 2:18:14 GMT
I really don't know enough about volcanos or calderas to know if the scientists are accurate but I have seen enough junk science used as fact in the global warming debate to not trust anyone. true, that. I've also seen enough people draw a unilateral conclusion based on partial data to question things that are presented as universal standards. |
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Post by GTCGreg on Aug 28, 2014 13:11:12 GMT
I really don't know enough about volcanos or calderas to know if the scientists are accurate but I have seen enough junk science used as fact in the global warming debate to not trust anyone. true, that. I've also seen enough people draw a unilateral conclusion based on partial data to question things that are presented as universal standards. Being presented as a "universal standard" and being one is not necessarily the same. The trick is to present your opinion as a "universally accepted fact." Debate settled. Just because no one's questioning the current view on a Yellowstone eruption doesn't mean that view is correct. Undisputed doesn't always mean correct. Nor does it mean "universally accepted." |
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Post by the light works on Aug 28, 2014 14:17:03 GMT
true, that. I've also seen enough people draw a unilateral conclusion based on partial data to question things that are presented as universal standards. Being presented as a "universal standard" and being one is not necessarily the same. The trick is to present your opinion as a "universally accepted fact." Debate settled. Just because no one's questioning the current view on a Yellowstone eruption doesn't mean that view is correct. Undisputed doesn't always mean correct. Nor does it mean "universally accepted." "opinion presented as fact" is currently a popular dismissal. |
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Post by wvengineer on Aug 30, 2014 13:04:17 GMT
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Post by the light works on Aug 30, 2014 13:10:16 GMT
well, it IS commonly considered that the same hotspot that built Yellowstone also built Craters of the Moon in Idaho - as well as a few other lava beds. so yeah, the pipeline could be getting closed off by movement of the crust. also, the fact that the period of Old Faithful is getting longer would imply that things are slowly getting cooler up there. |
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Post by wvengineer on Aug 30, 2014 14:40:39 GMT
So one questions that comes up is how long until the hot spot under Yellowstone gets closed off by movement of the plate? Although we are taking probably millions of years before that happens.
One thing I have wondered is if you know where a volcano is building pressure, could someone drill a line down to that point and pump off magma, thus reducing the pressure and likely hood of eruption. If you could release magma in a controled fashion, could you prevent an eruption entirely?
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Post by the light works on Aug 31, 2014 0:19:12 GMT
So one questions that comes up is how long until the hot spot under Yellowstone gets closed off by movement of the plate? Although we are taking probably millions of years before that happens. One thing I have wondered is if you know where a volcano is building pressure, could someone drill a line down to that point and pump off magma, thus reducing the pressure and likely hood of eruption. If you could release magma in a controled fashion, could you prevent an eruption entirely? interesting question, and probably one that will take physicists to answer. I know it would be mechanically challenging. hot magma is kind of rough on tools. I don't know if you need to release magma, or if transferring heat out of the hot spot would be sufficient to accomplish the goal. |
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Post by wvengineer on Sept 2, 2014 13:11:27 GMT
I had a good friend in college who was a geology major. I ran the idea of releasing pressure off a Volcano and he replied that he was not aware of it being done at all, but in theory, at least, it could work.
The biggest question is if the tooling could survive the heat and pressure as you mentioned, TLW. May be possible, but difficult and expensive. The other problem is that if you start releasing pressure from something that is already at some form of steady state, you have the potential for causing an eruption or earthquakes in a different way than you expected. So there is quite a bit of risk of unintended consequences.
In the end, while very costly and risky, it could be done in theory if there was sufficient motivation.
Where is Former Marine when you need some drilling experience?
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Post by the light works on Sept 2, 2014 13:55:20 GMT
I had a good friend in college who was a geology major. I ran the idea of releasing pressure off a Volcano and he replied that he was not aware of it being done at all, but in theory, at least, it could work. The biggest question is if the tooling could survive the heat and pressure as you mentioned, TLW. May be possible, but difficult and expensive. The other problem is that if you start releasing pressure from something that is already at some form of steady state, you have the potential for causing an eruption or earthquakes in a different way than you expected. So there is quite a bit of risk of unintended consequences. In the end, while very costly and risky, it could be done in theory if there was sufficient motivation. Where is Former Marine when you need some drilling experience? I have a feeling his "expertise" in other areas got challenged one too many times. |
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