1. The Layers of the Earth!

2. Earth Layers The Earth is divided into three major zones that are defined by their compositions. *Core (Inner and Outer) *Mantle *Crust

3. The Crust *The Earth’s crust is the thin, rocky outer layer of Earth *It is composed of the oceanic and continental crust *The crust makes up 1% of the Earth. * The crust of the Earth is broken into many pieces called plates.

4. Crust Oceanic crust is composed of basalt Continental crust is composed of granite Temp of crust - up to 870◦C Approx. 30 miles deep

5. The Mantle *. The mantle is the layer below the crust *The mantle is the largest layer of the Earth; over 82% of the Earth’s volume *The mantle is divided into two regions: the upper and lower sections.

6. Mantle 1,800 miles thick Temp – up to 2700◦ C Composed of dense rock and semisolid rock

7. Outer Core * The core of the Earth is like a ball of very hot metals; it is composed of an iron-nickel alloy. * The outer core is liquid. * The flow of metallic iron within this zone generates the Earth’s magnetic field.

8. Inner Core The inner core of the Earth is compressed into a solid state by the immense pressure. The inner core is a solid. Temp - 7200◦C Depth of up to 2100 mi

9. Lithosphere *The rigid outer layer of Earth, including the crust and upper mantle.

10. Asthenosphere Is the hotter upper mantle below the lithospheric plate; Can flow like silly putty; and Is a viscoelastic solid, NOT liquid!!

11. Seismic Waves *Seismic waves are the vibrations from earthquakes that travel through the Earth. *They are the waves of energy suddenly created by the breaking up of rock within the earth or an explosion.They are the energy that travels through the earth and is recorded on seismographs.

12. Types of Seismic Waves Surface Waves Body Waves  P waves  S waves

13. Surface Waves * Seismic waves that travel along the Earth’s outer layer. * They travel along the ground and cause the ground and anything resting upon it to move. *Surface waves are the most destructive earthquake waves.

14. Primary or p-wave * The first kind of body wave is the P wave or primary wave. This is the fastest kind of seismic wave. The P wave can move through solid rock and fluids, like water or the liquid layers of the earth. It pushes and pulls the rock it moves through just like sound waves push and pull the air. * Compression wave

15. Secondary or s-wave * Transverse wave The second type of body wave is the S wave or secondary wave, which is the second wave you feel in an earthquake. An S wave is slower than a P wave and can only move through solid rock. This wave moves rock up and down, or side-to- side.

16. Review 1) What are the three layers of the Earth? 2) The Earth’s crust is very ______? 3) The mantle is the largest layer of the Earth? True or False 4) Is the Outer Core a liquid or a solid? 5) What is the difference between p-waves and s-waves? 6) What are surface waves?

17. Answers! 1) Crust, Mantle, Outer Core, Inner Core 2) Thin 3) True 4) Liquid 5) P waves are primary waves and S waves are secondary waves 6) Waves that occur on the Earth’s crust. Cause the most earthquake damage.