Layers of the Earth
Prepared By: Maria Johanna Baguio Testa
Structure of the Earth
Layers of the Earth
Crust
- is the outermost layer of the planet
- makes up only 1% of the entire volume of the Earth, though it makes up the entire surface (the continents and the ocean floor).
Two parts of Crust:
- Oceanic crust - the thinner parts which underlies the ocean basins at a depth of 5-10 km (~3-6 miles).
- Continental crust - the thicker crust is the continental crust underlies beneath the continent.
Mantle
- makes up about 70-84% of Earth's volume
- is predominantly solid, but behaves as a very viscous fluid in geological time.
Mantle is divided into two:
- Upper mantle (Lithosphere and Asthenosphere)
The uppermost mantle and the overlying crust form the lithosphere, which is relatively rigid at the top but becomes noticeably more plastic beneath.
- Lower mantle (Mesosphere)
The lower mantle lies between 660-2,891 km (410-1,796 miles) in depth.
Very little is known about the lower mantle apart from that it appears to be relatively seismically homogeneous.
Core
- Located at the center of the Earth.
- Made up to 30-33% of the Earth’s landmass
Two parts of Earth’s core:
- Inner core
The inner core is composed primarily of iron and nickel
The inner core is the very center of the Earth, and the hottest part of the planet. It is a mainly a solid ball with a radius of about 1,220 km (760 mi), according to seismological studies.
- Outer core
The outer core, which has been confirmed to be liquid (iron and nickel) (based on seismic investigations)
Is believed to be composed of 80% iron, along with nickel and some other lighter elements.