What is a volcanoe?

A volcanoe is a opening or rupture in the planets surface or crust, this allows hot molten rock, ash and gasses that scape from below the surface. Volcanic activity that has extrusion of rocks tends to form mountains over a period of time. Volcanoes are most found on tectonic plates (diverging or converging). Volcanoes are also formed when there is streching and thinning of the earths crust. Volcanoes can be caused also as mountain plumes, these also called hotspots for example at Hawaii, can occur far from plate boundaries