World’s Largest “Supervolcano” Is Even Bigger Than Previously Thought (Yellowstone)
It matters not one bit HOW BIG the magma chamber is. What matters is how much material is blasted out and what kind.
The model on this site tells the story as far as the size of past volcanic eruptions.
And yes, Yellowstones chamber is the biggest, but it really is mathematical impossible for it to expel all that magma-according to geologists who have studied it. The chamber cap will collapse long before as the pressure drop will not be able to hold the surface up. The best guesses I have seen is that about 1/3rd, or so, of the magma would be released. After the cap drops, the remaining pressure releases and the volcano is done...for a while.
The result? Worldwide devastation. It is not the ash that causes the problem, although bad in itself, ash would cover much of the USA. But, the gases would envelope the earth causing huge climatic change.
The Long Valley caldera is acting up. If you have interest in these things, take a long look at whats going on there these past weeks/months and years. The magma there is ABOVE the valley floor. Its up into the hills and mountains and a side eruption is going to happen. Think Mt St Helens. That was a side eruption caused by a unstable surface that slid and allowed the eruption to happen.