1. Earthquakes
Shake, Rattle and Roll

2. Types of stress (notes are in yellow font with light blue background pg. 45
Tension- a type of stretching force
Compression- forces that squeeze (compress)
Shearing force – pushes rock layers in two different direction

3. - Forces in Earth’s Crust

4. - Forces in Earth’s Crust

5. - Forces in Earth’s Crust

6. - What type of stress would cause a normal fault?

7. - What type of stress would cause a reverse fault?

8. - What type of stress would cause a strike slip fault?

9. Do you see folds or faults?

10. Types of faults (page 46-47

11. Faults and Folds
A break or crack along which rocks can move is a Fault
A fold is a bend in rock layers without a break or crack.

12. - Forces in Earth’s Crust

14. - Earthquakes and Seismic Waves

15. Epicenter and Focus
The Epicenter is the point on the Earth's surface that is directly above the Focus, or point where an earthquake originates.

16. P – wave or Primary Wave
The primary waves have the highest velocity of all seismic waves and are the first to arrive at any seismic station and can pass through liquid layers of the Earth
Sound, as a compressional wave is also a longitudinal wave

17. - Earthquakes and Seismic Waves

18. S-(Secondary Wave)
The S-wave moves as a transverse wave, so motion is perpendicular to the direction of wave travel.
It is S-shaped, like waves in a rope, move slower than p waves and cannot travel through liquids

19. S waves curve like an s. They are secondary and slow

20. L- waves
L (Love) waves dissipate (weaken) slowly due to the huge amount of energy that they contain.
They are the most destructive around the area of the focus or epicenter of an earthquake.
They are what most people feel directly during an earthquake.

21. - Earthquakes and Seismic Waves

22. - Earthquakes and Seismic Waves

23. Richter scale
Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; in terms of energy, each whole number increase corresponds to an increase of about 31.6 times the amount of energy released, and each increase of 0.2 corresponds to a doubling of the energy released.
Charles Richter circa 1970

26. Potentially perceptible
Description
Magnitude
Frequency per year
Great
8.0+ 1
Major 18
Large (destructive)
120
Moderate (damaging)
1,000
Minor (damage slight)
6,000
Generally felt
49,000
Potentially perceptible
300,000
Imperceptible
less than 2.0
600,000+

27. One of the worst ever
The great Alaska earthquake of March 27, 1964, is the largest earthquake in the United States. It had an esitmated magnitude of people died, with most of the deaths due to the tsunami it generated.
Shaking was felt for an estimated 7 minutes, and raised or lowered the ground surface as much as 2 meters (6.5 feet) in some areas and 17 meters (approx. 56 feet) in others. The length of the ruptured fault was between 500 and 1,000 kilometers (310.5 and 621 miles).
The amount of energy released was equal to 12,000 Hiroshima-type blasts, or 240 million tons of TNT.

28. - Earthquakes and Seismic Waves

29. - Earthquakes and Seismic Waves

30. Video
On seismic shadows

31. where:
k is the modulus of incompressibility
μ is the modulus of rigidity; and
ρ the density of the material through which the wave is propagating

32. - Monitoring Earthquakes

33. - Monitoring Earthquakes

34. - Earthquake Safety

35. - Earthquake Safety

36. Base Isolated Building
With u shaped lead dampners
And rubber isolation pads
(Video- 2:30 to 4:30)