One of the recent signs that an eruption may be coming soon is evidence from a small city in the region of Vesuvius, where it seems like the sea is falling. But, really the town has been rising at a rate of more than 11 feet a year for the last 30 years. A magma chamber underground is rising and pushing the land upwards. Once the pressure builds enough, the magma will need somewhere to go, and it will either erupt where it is or be forced through a new volcanic opening nearby.

This presents a pretty interesting dilemma. If I were living in that little town where the magma is rising, I might actually not decide to move. I mean if I have lived there all my life, or I really like it, would I want to move because someday something might happen? That seems to be a big theme with volcanoes. How do you know when something is going to happen and what do you do about it? What kind of a risk are you willing to take?