My statement of "should" there could be construed as saying what should be happening based on volcanology when you suddenly surround a volcano with a mass of ice, which isn't necessarily eruptions, or it could be taken as "What we should be doing to make Atamara a more interesting continent to play on".
Who said the Volcano isn't extinct? Or the Snow Trolls and Ice Demons didn't do something to prevent this? Maybe a Wizard did it. A wizard probably did it.