Tectonic plates is the study area of the formation of volcanoes.Their are different types of plates boundaries and the type of boundaries that cause volcanoes are sub suction Zones. Subduction zones occur where an oceanic plate meets a continental plate and is pushed underneath it. Subduction zones are The descending end of the oceanic plate melts and creates pressure in the mantle, causing volcanoes to form.(There are 3 main boundaries).