It won’t blow until something from below makes the magma chamber swell to an unstable state.
Exactly. If you could simply make openings at the surface (I count that as a few kilometers down too) then we would never have an eruption because we could poke holes above the magma chamber.
Super-eruptions start deep below the earth and the energy is hundreds of times larger than the pool of magma sitting in the upper chamber. For a massive Yellowstone eruption the magma that sits in the chamber now is no more consequential to the eruption than the piece of cork at the top of a wine bottle. Get enough gas generation in the bottle and the cork will be expelled with a rush of liquid behind it.
Most people don't realize just how big and powerful vulcanism really is and super volcanoes are orders of magnitude more powerful than an "average" volcano. It's understandable that they don't. It's hard to wrap the mind around how much energy is at play there.
As for missiles penetrating the magma chamber, I don't think any "bunker buster" missiles ever created can penetrate 4 to 10 miles of solid rock.
These forces are just insane.
What?! You can’t be making rational, fact based posts around here! /s
(Sad that I have to add the “/s” for some people, isn’t it?)
Anyway, good explanation! Better than the one I was writing, but, I’m kinda distracted by “incoming” weather, too.
I suppose it might be possible to get something like a Mt. St. Helens type bang if one could get the lake to drain down to the magma. (Steam explosion.) But, that seems very unlikely, and it’s still nowhere near a super-eruption.
I’d add that super eruptions are not necessarily incredibly intense “bangs”. They just go on and on. Krakatau was actually a more intense bang than Tambora, but Tambora erupted with force, longer. Eruption ratings are based on total energy released or total material ejected, not peak numbers.