Oh I get it! If you stack rock on the hot rock, you can stop the hot rock from moving the rock with more rock!

… Unironically, this DOES work … sorta’. Though it’d be dumb to do by man, because a ‘rock plug’ is exactly what forms at the top of many volcanos after the magma cools. It’s why many volcanos have flank eruptions where magma pushes through some side crack, or build and build until the rock plug pops catastrophically.

Of course some volcanos don’t have the right mix to form rock plugs, and any non-dormant volcano can pop them, but the point is it does have an effect that can delay and redirect eruptions.

If humanity doesn’t kill itself off soon (bad news on that front), I wouldn’t be surprised if one day we’re building megastructures around volcanos specifically to manage them instead of being subject to them.