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Earthquake Lake along the Madison River in Montana, just west of Yellowstone Park.
There have been three VEI8 (Volcanic Explosivity Index [level] eruptions at Yellowstone, the first being 2,100,000 years ago, the second being 1,300,000 years ago and the most recent being 640,000 years ago. While the average interval between them works out to be about 730,000 years this is only taken from two samples, of intervals of 800,000 years and 660,000 years - hardly a good basis for making an accurate estimate.That the Yellowstone system is still very much active is beyond doubt, and it is entirely possible that another VEI8 eruption might occur there, but as to when, if ever, it will occur is completely open to debate. For example if, instead of comparing the average interval with the most recent recent interval, we go by the interval between the first and second eruptions, then far from being overdue another VEI8 eruption we've still got another 70,000 years to wait.What is much more likely, and even probable, is that a minor eruption will occur 'soon' - perhaps even sometime in the next few thousand years. Such an event would be entirely in keeping with the known behaviour of the Yellowstone system, which has had many more smaller eruptions than the large VEI8 ones, the most recent being about 70,000 years ago.
Wouldn't the destruction of the Yellowstone Park in the Rocky Mountains possibly start off another volcano in the Mt. St. Helens as happened in the early 1980s? Unless I have my geography all over the place. That's possible.
Does this mean no more Boo Boo ?
I would normally let Bass answer this since he practically lives in Yellowstone and is a compendium off erudition about this subject. But since Bass is playing Paul Bunyan this week - he has delusions, you know - it seems that I should address this subject with the knowledge available in my own complete compendium of Geologic Knowledge.
Lee is correct - it is a mantle plume.
But the evidence for the hot spot goes back a LOOOOOONG time. 100 Million years at least.
Unlike the Hawaiian Islands, which are formed from basaltic lava, the Yellowstone hot spot has rhyolitic lava. This is because the lava is formed by the remelting of the continental crust, which has a lot more silica in it than the crust below the oceans have. The Hawaiian volcanoes are probably a result of remelting of oceanic crust and the material of the hot spot plume itself.
The map below shows the trail the hot spot as the continent has moved over the hot spot.
Because the older rhyolites are small and mostly covered by newer basaltic eruptions it is difficult to find the caldera from 70 Million Years ago.
It has been suggested that the evidence points to this super volcano having erupted at 600,000 year intervals in the past and it is roughly 623,000 years since the last eruption.‘Old Faithful’ continues to live up to it’s name, which might suggest that the volcano is, for the time being at least, stable. But is it? Does anyone really know the current state of the Yellowstone Park super volcano?What would happen if it were to erupt in the next few years? Would the consequences be far too dire to be imagined? Would it cause a mass extinction which would render the planet uninhabitable for the human race?Doomed, doomed I tell you, we’re all doomed!
The plume would have to punch through two plates (the Juan de Fuca and N. American) to reach the surface. It would seem (in a wholly unlearned view) that the two plates would form some kind of magma trap between them. I know that the Farallon has very shallow subduction in the SW US, but I'm not sure the same holds true in the NW.
I was about to chastise you on how WRONG you are in implying such a small basin and range - placing such a limited area as the area of the Basin and Range just between the two arrows. This is just the northern limit of the Basin and Range. The Basin and Range extends all the way into northern Mexico! Parallel ridges in Arizona, Walker Lane Fault Zone, all of Nevada.. all of this is the modern expression of the extensional tectonic zone. It is everything from the Colorado Plateau to the Coastal ranges of California. The San Joaquin Valley is extensional tectonics. and on the east the Rio Grande Rift is extensional Tectonics. It is a HUGE area!