I'd call it meaningless, literally. A volcanic eruption on an uninhabited planet is an incredibly violent event, but trying to assign alignment to it would be misguided. You'll also note that, by D&D rules, a tiger violently killing a gazelle is a neutral activity, specifically because the tiger is not able to rationalize its behavior. An act of violence only has any weight in the alignment system when it is performed by a being with a motivation.