Formation of Volcanoes - at destructive boundaries
Oceanic plate subducts under the continential plate. Oceanic plate is melted and destroyed, then a pool of magma forms. The magma rises through crack in the crust.The magma erupts onto the surface, forming a volcano.
At constructive boudaries -
Magma rises up into the gap, this gap is created by the plates moving apart. This forms a volcano.
Some volcanoes also form over parts of the mantle that are really hot. These are called hotspots e.g. in hawaii
Three different types of volcanoes -
Composite - e.g. mount fuji in japan - made up of ash and lava that has erupted, cooled and hardened into layers. The lava is usually thick, flows slowly and hardens quickly.
Shield - e.g. Mauna Loa - in the hawaiian islands - made up of only lava which is runny, flows quickly spreads over a wide area, forming a low, flat volcano.
Dome - e.g. mount Pelee in the caribbean - made up of only lava, the lava is thick, flows slowly and hardens quickly to fro a steep sided volcano.
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