Use the workbook to complete the following chart: Fault Direction Diagram Stress 1. 2. 3.

1. Use the workbook to complete the following chart: • Fault Direction Diagram Stress • 1. • 2. • 3.

2. Where do Earthquakes Happen? Finish the activity!!!!!!!!

3. Earthquakes

4. What is an Earthquake? • An earthquake is a vibration of the earth caused by the release of energy from crustal movement • 1 million each year • Not strong enough For us to notice

5. Why do earthquakes happen? • The edges of plates often get stuck together even though tectonic forces are trying to move them • Stress (elastic energy) builds up • The rocks at the weakest point break suddenly shifting the earth’s crust • The sudden movement of the earth’s crust releases energy in the form of seismic waves = EARTHQUAKE

6. Identifying their origin • Seismos – “to shake” • Focus – point within the earth where the earthquake starts • Epicenter – location on the surface directly above the focus

7. Aftershocks – smaller earthquakes that follow a major earthquake • Foreshocks – smaller earthquakes that precede a major earthquake

8. Measuring Earthquakes • Seismologist – one who studies earthquakes • Seismograph – instrument that measures seismic waves • Seismogram – wiggly graph that a seismograph produces • Seismic Waves spread out in all directions from the focus (Surface and Body Waves)

9. Richter Scale • Developed in 1935 • Measures the amount of energy released by an earthquake • Uses magnitude (powers of 10) • Scale from 0-10 • 5.0 is 10x stronger than a 4.0

11. 3 Types of Seismic Waves • Primary Waves (P waves) • Push and Pull waves (squeezes and stretches) • Travel through solids and liquids (outer core) • Do not do damage • Fastest of the 3 waves (1.7 x faster than s waves)

12. 3 types of Seismic Waves • Secondary Waves (S – waves) • Move at right angles (zigzag) • Travel through solids only • Slower than P waves but 90% faster than surface waves • Do not do damage

13. 3 types of Seismic Waves • Surface Waves (L-waves) • Travel along the surface • DO DAMAGE • Up and Down AND Side to Side waves • Slowest of the 3 waves

14. Exit Matching • L wave a. move fastest • S wave b. do not move through liquids • P wave c. cause damage • Seismic wave d. energy released by an earthquake

15. Distance (lag time between p and s waves) The lag time between p and s waves determine the distance to the epicenter of an earthquake.

16. Location (triangulation) We do not know the direction from which the seismic waves came from BUT because we know the distance we can use 3 stations to pinpoint the epicenter

17. 3 major earthquake zones • 1) Mid-Atlantic ridge • 2) Mediterranean-Eurasian Belt • 3) Ring of Fire • New Jersey Earthquake Potential =

19. New Jersey Earthquakes

20. Earthquake Dangers • 1) Shaking causes building destruction • 2) Tsunami • 3) Landslides • 4) Fire