Your question (which I am presuming is deliberately factious) is a loaded one. It presupposes that God exists. In my opinion, He doesn't. Ergo, the question is epistemologically invalid.
That being said, let us suppose that God does exists and that the volcano does erupt violently, resulting in multiple deaths. What then?
Well, I would argue that God is evil since He either caused or allowed to be caused the deaths of people who would otherwise have gone on to live their lives. If one were to argue that all the people who perish in a fatal volcanic event were despicable individuals then why would a God (who, let's not forget, is an all powerful creator deity that can literally bend and shape reality to whatever He chooses) resort to such a blunt instrument in order to punish them when He could so easily admonish them in so many other subtle and individualistic ways? God, it would seem, paints with a very broad brush.
If God is truly real, He would not allow innocent people to suffer. The fact that they do is reason enough to conclude that God is a man-made construct and a fantasy.