1. Earthquakes Earth shaking

2. Basic Earthquake Words: The epicenter and focus Force pushing Force pushing Fault is a crack That forms Along the break An Earthquake is the group of waves that spread away from the focus

3. Earthquakes require a brittle-solid that breaks – the lithosphere - force builds but no shape changing shape, not plastic - break/shatters when force large enough - Earth material (rock) goes twang, energy released as earthquake waves Lithosphere: (plate) brittle solid, strong earthquakes Mantle: plastic – oozes Outer Core: liquid Inner Core: solid

4. Earthquakes are concentrated around plate boundaries Depth of Focus: 0-70 km 70-300 km 300-700 km Plates

5. (Garrison, 1993) Pressure, Primary (P) waves: - squeeze - slinky push-pull - faster than sideways wave in Earth - travels through solids and liquids - Ex: sound only pressure wave Sideways, Secondary (S) waves: - rope wiggle - slower than pressure wave in Earth - travels through solids, NOT liquids Solids transmit P and S waves - Sudden force in a solid makes P and S together, usually cannot separate - Example: smack board with hammer Earthquakes Exist In the Form of Waves: Most expressed are P & S

6. Actually, there are three types of Earthquake waves P=Pressure wave Slinky push-pull, Caterpillar scrunch Fastest, 1 st to arrive S=Shear wave Sideways wiggle Slinky sideways wiggle Rope wiggle Slower, 2 nd to arrive Surface Wave Only travels on a surface, Maximum movement on surface, Movement decreases away from surface, Movement disappears far enough away from surface Slowest, 3 rd to arrive Causes Most of the Damage 2 Flavors Of Surface waves

7. An earthquake in lithosphere (plate) makes P, S and Surface waves that spread outward in all directions If the Earth were uniform, stronger P and S waves would travel inside in straight lines through the entire Earth. = focus Surface Waves Only travel On the surface

8. Seismometer Recording of an Earthquake: A record of the winners of a race with P arriving first, S second, Surface last

9. P & S waves inside the Earth - do not travel in straight lines - take different routes Can’t Be Observed Explanation requires A Non-uniform Earth

10. The San Andreas Fault: Our nearest plate boundary

11. Lakes. <>

14. Japan’s Earthquakes

15. The End