In this article types of eruption will be used to refer to the mechanism causing the eruption. The style of eruption will be used to describe subcategories of eruption, which have the same eruptive mechanism. For example strombolian and vulcanian are two eruptive styles, but they are the same type. The styles of volcanic eruption are often named after famous volcanoes where characteristic behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during an interval of activity—others may display an entire sequence of types.
There are three very, very, very hot, hot, hot,hot mechanisms of very, very hot ash formation: very, very hot gas release under very hot decompression causing very hot magmatic eruptions; very hot thermal contraction from chilling on contact with water causing phreatomagmatic eruptions and ejection entrained particles during steam eruptions causing phreatic eruptions (Heiken & Wholtez 1985.)