What causes a volcano?
Volcanoes are formed when two tectonic plates of the earths crust move.Tectonic plates float on magma also called lava,magma is able to squeeze through the gaps.Vulcanologists study volcanoes and are trying to figure out a way to warn surrounding towns when a volcano is going to erupt.Some volcanoes give no warning when they’re going to explode,many people can be killed and damage can cost millions of dollars.Not all volcanoes are dangerous some volcanoes don’t explode only smoke comes out of the tip. Some people like volcanoes because their crops grow very well in the soil, Volcanoes produce beautiful gems.
An interesting fact is there are volcanoes in outer space.
Indonesia have the most active volcanoes there are around 1500 active volcanoes there are so many because Indonesia in the centre of four tectonic plates the Australian Philippine Eurasia and the pacific.

Click on this image to watch a video showing how a volcano erupts.