Presentation is loading. Please wait.

Presentation is loading. Please wait.

Structure of the Earth.

Similar presentations

Presentation on theme: "Structure of the Earth."— Presentation transcript:

1 Structure of the Earth

2 Earth’s Compositional Layers

3 How do we know? Echo-sounding techniques are used to explore the Earth's crust. Images, similar to sonograms, are produced. A sonogram in the crust is called a seismic reflection. Seismic waves from "small explosions or thumper trucks" return echoes from rock layers. Seismographs pick up these echoes.

4 How do we know? continued
Seismic measurements from earthquakes P waves and S waves P waves are primary waves, they travel faster than S waves, which are secondary waves P waves are compression waves, exerting a force parallel to the direction of travel P waves can travel through liquid or solid S waves are shear waves that exert a force perpendicular to the direction of travel S waves can only travel through solid media

5 How do we know, continued

6 Crust 5 – 80 km thick two types: Mostly made up of silicate rock
oceanic - thinner and more dense 5 – 10 km thick Continental – thicker and less dense 15 – 80 km thick Mostly made up of silicate rock Comprises only 1% of Earth’s mass

7 Mohorovicic Boundary between crust and mantle

8 Mantle 2900 km thick Iron Comprises 66% of Earth’s mass

9 Core Radius of 3500 km Iron and nickel Comprises 33% of Earth’s mass

10 Structural Zones Lithosphere Asthenosphere Mesosphere Outer core
Inner core

11 lithosphere 15 – 300 km thick Comprised of crust and upper mantle
Brittle, cool portion of Earth Outermost layer

12 Asthenosphere 200 – 250 km thick
Solid, but with ability to flow (plasticity)

13 Mesosphere Lower portion of mantle Extends to 2900 km beneath surface
Solid rock

14 Outer core Extends to a depth of 5150 km beneath surface
Dense liquid metal

15 Inner core Dense, rigid solid

16 Earth’s 4 “Spheres” of study
Geosphere Hydrosphere Atmosphere Biosphere



Download ppt "Structure of the Earth."

Similar presentations

Ads by Google