The Earth's Structure by Ashley and Belinda The Earth might seem like one piece of solid rock, but it is not really like that at all. The earth is divided up into three different layers the core , the mantle and the crust. The core is in the centre of the Earth and is divided into an inner core which is solid and about 2 500km thick and an outer core which is liquid and about 2 200km thick. The inner core generates a magnetic field that protects  the Earth's from flying out of orbit. The region just below the crust and above the core is the mantle. It is about 2 900km thick. The mantle is made of molten rock and is relatively flexible so it flows instead of breaking. The crust is the next layer,which is the top layer of the Earth.  It is basically hardened mantle(magma) and it is from 5 to 50 km thick depending on where you are.  It contains two segments,oceanic and the continental crust.This is the same crust, but if it is under the ocean, it is called oceanic crust and if it forms land, it is called continental crust.  For instance if you  drained all the water from the earth, then there would be one, giant continental crust or if you flooded everything you'd have one giant oceanic crust. Continental drift,volcanoes and earthquakes are all caused by the Earth's structure. Click HERE to see our model of the Earth's structure.