Earth's internals structure
Crust: hard and rigid, it's earth's outermost and thinnest layer, only 5 km thick under the oceans and averaging 30 km thick under the continents
Mantle: Subdivided into two regions, upper and lower, this dense layer made of hot, semi-solid rock is located directly below the crust and is about 2900 km thick
Outer Core: The outer core is the only liquid layer of the earth - a sea of mostly iron and nickel. it is roughly 2890 to 5150 km below the surface and is about 2300 km thick
Inner Core: An extremely hot, solid sphere of mostly iron and nickel at the centre of the earth. it is 5150 to 6378 km below the surface and about 1200 km in diameter.