Our planet has 4 layers.
The crust is the thin outer layer around the earth. Under the crust the The next layer is the mantle and it is 1880 km thick. The outer core is made with liquid that is very hot and it is beneath the mantle is the center of the earth is called inner core. The crust is broken into humongous pieces called tectonic plates. The tectonic plates are moving slowly all the time. When they pull apart, the magma in the mantle will start to push up. When the magma comes to the surface it is called a volcanic eruption. Once the magma comes out it is called lava. When the lava cools down it turns into rock. As more lava comes out the volcano builds up into a cone shape.
Farming-did you know that the richest soil is mostly found in a volcanic eruptions. The volcanic eruption can help the vegetables to grow because volcanic rocks are filled with minerals and nutrients.
Negative
Did you know that people drill into the crast of the earth to get the heated water and steam so they can get electricity in the power plants.
In Indonesia at 1815 there was a volcanic eruption and it was one of the world's biggest volcanic eruption. The next summer in America the weather changed and it was very cold and snowy .This volcanic eruption was so big that the ash blocked out the sunlight.
The ash can stop the plans from flying and if they fly they will crash because when the ash goes into the engine that engine will stop working.
Glossary
Ash/pungarehu
Ash is a lot of pieces of lava that comes out of a volcano.
Crust/kirinuku
The crust is the first layer of the earth.
Erupt/pupunha