My story for a video game has some kind of "enemy" (think "the Others" from Lost—little is known about them; they have control over a small settlement or two and appear to be engaging in some manner of industry involving a network of abandoned coal mines).
I'm not really looking to flesh this back-story out since I might do that myself, but I have the opinion that an unexpected volcanic eruption is going to be a good premise for a "run-for-your-life" part of the game.
It's occurred to me that a volcano and coal mine are two kinds of "rather deep holes in the ground". So how can a small team of careless idiots in charge of mining equipment accidentally cause an eruption? Is it really just a case of digging?