Earth Systems: Interior of Earth

Earth Basics ≈ 71% Earth’s surface covered with H2O Slightly flattened sphere “oblate spheroid” Surface is fairly smooth 3rd planet (rock) from the sun 5th largest planet (12,756 km diameter) Gravity – force of attraction between matter (6 times greater than the moon!)

Earth’s Interior

Earth’s Interior Properties determined by changes in speed and direction of seismic waves Seismic waves are vibrations that travel through Earth

Compositional Zones: Crust – thin outermost layer of Earth above the mantle Oceanic Crust – beneath the oceans (5 -10 km thick) Continental Crust – makes up the continents (15 – 80 km thick) Mantle – layer of rock between the crust and core Core – central part of Earth below the mantle composed of Iron and Nickel

Compositional Zones

Structural Zones: Lithosphere – solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle Asthenosphere – solid, “plastic like” layer of the mantle which can flow and move the tectonic plates above it Mesosphere – the middle sphere, strong, lower part of the mantle, made of solid rock

Structural Zones: Outer Core – dense liquid of iron and nickel Inner Core – dense rigid solid of iron and nickel

Earth is Magnetic Two magnetic poles create magnetic field surrounding Earth May be caused by movement of liquid iron in outer core Sun and moon have magnetic fields but sun has no iron and moon has no liquid outer core As liquid moves, electric currents create magnetic field

Earth’s Magnetic Field