- THE CRUST: It’s where we live! As you can see from the diagram it’s pretty thin compared to the other layers. At it’s thinnest its only 5km thick, at its thickest it is 50km.
- THE MANTLE: This is like a solid but can flow like a liquid (very slowly). Radioactive decay happens here, which produces heat and causes the mantel to move about on convection currents.
- THE OUTER CORE: Made from liquid nickel and iron.
- THE INNER CORE: Made from solid nickel and iron.
Surrounding the whole thing is the atmosphere.
NOTE: The crust and mantle together are called the “lithosphere”.
The crust and the upper bit of the mantle are split into tectonic plates. These float on the mantle and the convection currents within the mantle cause them to drift about.
The plates only move a few centimetres a year relative to each other but this can happen very suddenly which causes an earthquake. Volcanoes and earthquakes all occur at the boundaries of the tectonic plates.
Unfortunately scientists don’t know when sudden movements in the plates will happen.