Hi As we understand the structure of the Earth: 1) The CRUST - 10-70 km. 2) The MANTLE - down to a depth of 2900 Km. 3) The OUTER CORE - down to 5100 km. 4) The INNER CORE - down to 6370 km. As you see the part of the earth's interior below 2900 km is called the CORE. It is believed to be ...