1. Uplift: Faults and Earthquakes
Vibrations in rocks caused by a release of energy when rocks break at fault planes or plate boundaries Ex. San Andreas Fault

2. 1. Three types of stress
Tensional: at diverging boundaries: Normal faults
Compressional: converging boundaries: Reverse faults
Shear: transform boundaries: strike slip faults

3. 2. Why rocks move Plate movements ->stress_-> strain in rocks.
This stored “elastic strain energy” makes rocks deformed
When rocks cannot handle stress any more, they rupture releasing energy as seismic waves: EARTHQUAKE!!!
Elastic Rebound: rocks snap back to original shape but are OFFSET (displaced)
Lab: Trabuco fault lab

5. What type of fault?

6. Normal: Hanging wall slides down
Tensional stress

7. What type of fault?

8. What type of fault? Reverse: Hanging wall slides up:
Compressional stress

9. What type of fault?

10. What type of fault?
Transform fault: Right or Left lateral??

11. 3. epicenter, focus of e.q.

12. C. Released energy travels in the form of Seismic waves

13. 4. Properties of waves
P – primary waves: 1st to arrive; ~7 km /sec.; compressional; travels through air, water, solids S – secondary: 2nd to arrive; shear or right angles, ~3-4 km/sec.; solids only L – Love and Rayleigh waves: slowest; last to arrive; most destructive

14. P - push pull waves
P - push pull waves
                                                                                                        

15. S - shake or shear waves
S - shake or shear waves
                                                                                                       

16. L - surface waves: surface waves
                                                                                                                              

17. 5. Recording an earthquake’s time, Duration, Magnitude, Location, Energy
Seismometer: Drum and seismogram paper
Seismogram: graph of waves shows time of ground shakings:
1.It gives time quake occurred
2. Duration
Lag time- gives 3. location (with TT graph) and 4. magnitude (with Richter scale)
Amplitude- gives magnitude

18. Time: when it occurred:

19. Duration
Measure from the beginning of P-wave to end of S-wave

20. Lag time =S-P; and Amplitude
Used to find magnitude, energy
Used to find epicenter – location
Amplitude used to find magnitude

21. Finding Magnitude: Use lag time and Richter’s Scale
See Richter’s scale worksheet
Each number is exponentially 30 (32) times greater than the previous number
Ex.How much stronger is Mag. 4 than mag.1? Ans.= 303 = 27,000x

22. Finding the epicenter
1. Use a Time travel graph and Lag time to get distance to epicenter from one city

23. Travel time graph S-P = Lagtime is measured on vertical axis
Horizontal axis gives distance to epicenter for each station

24. Graph shows P, S, L times

25. Finding epicenter… continued
2. Get distances from three(3) cities.
3. Distances = radii from cities
Use scale of map to measure distances and draw three circles
4. Where radii intersect is the epicenter

26. Finding the epicenter

27. S and P shadow Zones