Generally speaking, it’s pretty easy to tell when something is going on with a volcano. When a large volcano is about to blow its top it typically shows signs of unrest many days, months, or even years ahead of time. Add to that the fact that many volcanos are constantly monitored and are popular with sightseers and you can understand why the vast majority of volcanic activity is easy to observe and study. When the Havre volcano produced a massive eruption several years back scientist not only didn’t predict it, they actually almost missed it entirely.
