One of my favourite things to study about was Volcano's. I found out the different parts and that volcano's erupt along the cracks that are opened in the ocean floor by the spreading of two plates called a mid-ridge. Also Magma rises from the earths mantle up to these cracks. The volcano erupts by the molten rock stored in the magma chamber rises through the crater pipe pockets. As it travels through the main vent gasses expand and water becomes steam, creating pressure. When the pressure can no longer be contained, The volcano erupts though the crater and secondary side vents.
Common volcanic gasses include water vapour, carbon dioxide, sulphur dioxide, hydrogen chloride, hydrogen fluoride and hydrogen sulfide.
A popular belief is that volcanoes are a certain cone shape but that's not true there are many types of volcanoes such as wide plateaus, fissure vents and bulging some shapes.
Facts about Volcanoes:
1) The name volcano originally came from the Roman god of fire ''Vulcan''.
2) The tallest volcano in the solar system is not on earth at all. But it is on Mars
3) Approximately 350 million people live within “danger range” of an active volcano.
4) Volcanoes can also occur over ''mantle plumes