"Putting a stop to evil" is not the specific, guaranteed outcome of a nuclear detonation in a war situation. Killing people and destroying stuff is the specific outcome - just as it is for a conventional detonation - and those are objectively bad outcomes. That's why I said "Evil that deters greater evil."
A nuclear detonation as a propellant in space wouldn't really be a "nuclear bomb," but a thruster. Using one on a volcano would be stupid, imo.
There are some nice people in Los Angeles.
Using one to stop evil, even if that’s not the outcome, might still be a good thing.
Using one in a volcano might not be noticed given the force of volcanos, but I would leave it up to the scientists making the proposal whether to seal the volcano and how. There was a movie about a volcano in LA.
I’ll give you the semantics on propellant vs. bomb but it would probably be the same mechanics.
I’m not saying any more about LA.
Since the explosion of the nuclear bomb occurs in three dimensions, it is difficult to make it properly serve as a thrusting device. It is workable to do so, however, by the immensity of its energy release. For its weight, a warhead packs a lot of punch, and even though much of the explosion is lost to a non-intended direction, what is transferred to the pusher plate is very powerful.
The momentum transfer, therefore, can actually not only work as a solar-system transportation scheme, but also as a potential interstellar mechanism.
Perhaps the better way to look at it is that it is a way to get rid of a whole bunch of nuclear warheads, for which little better purpose could be imagined.
"Using one on a volcano would be stupid, imo."
It's hard to see how using an explosion to deal with an explosion can be a good idea.
It's not impossible, of course. But this isn't a Red Adair operation in which the oil-well fire has to have its flame and the oxygen which feeds it interrupted for a moment.
The only way I can envision using a nuke on a volcano is to direct its subsequent outflow in a less-harmful direction. Even that seems monumentally trepidatious.
Since the nuke explosion could not quench the volcano in any way, it could only serve to allow the volcano to vent and belch even more, perhaps settling down into a continuous rather than intermittent eruption. To the scientist who wants to use this procedure, I would suggest allowing the rest of us to observe from a safe distance away from it, like on another planet.