UNIT 4 LESSON 6 – MEASURING EARTHQUAKE WAVES 1. An earthquake occurs when 2. Earth’s lithosphere is 3. Stress causes ____________________________ to form. 4. A fault is 5. Stress causes rocks to deform, when rocks deform, they _____________________________ from their original shape. 6. If stress becomes too great, rocks along the fault will ______________________ and ______________________ along the fault. 7. Once rocks break, the pieces of broken rock return to an ____________________________________ shape. 8. When rocks along the _________________________ break and move along the fault,_________________________ is released into the surrounding rock in the form of _______________________________. 9. This process causes _______________________________________. 10. Focus – 11. Epicenter – 12. Seismic waves – 13. Body waves – waves that travel through the Earth’s interior. Surface waves – only travel along the surface not through the Earth. P waves (primary) Speed (relative to each other) Motion in rock Can travel through… 14. Seismometer – 15. Seismogram – 16. How is an earthquakes epicenter located? 17. Magnitude – 18. Intensity - 19. How is earthquake magnitude measured? 1. Richter scale – 2. Moment Magnitude scale – S waves (secondary) L waves (surface) 3. Mercalli scale – 20. What factors determine the effects of an earthquake? 1. Magnitude (explain)– 2. Local and surrounding geology a. solid rock – b. Loose soil saturated with water (liquefaction)– c. Distance from the epicenter – d. Building construction a. Building material – b. Mass damper – c. Active tendon system – d. Base isolators – 3. Distance from the epicenter (explain) – 4. Population of the area (explain) – 5. Intensity (explain) –