1. Bellringer Vocab Quiz TODAY!!!! Test Wednesday Direction
Type of Stress
Plate Boundary
Type of Fault
Pulling apart
Pushing together
Horizontally sliding

2. Earthquake Effects

3. Origin of an Earthquake
Focus – the location (usually several km below Earth’s surface) where an earthquake originates
Epicenter – the location on Earth’s surface that is directly above the focus
The closer the focus is to Earth’s surface, the worse the effects of the earthquake

4. Seismic Waves Seismic Waves – ground vibrations during an earthquake
Begin at the focus and spread out from there

5. Seismic Waves Three types of seismic waves: Primary Waves (P-Waves)
Secondary Waves (S-Waves)
Surface Waves (L-Waves)

6. Primary Waves (P-waves)
Fastest-moving seismic waves
Rocks are squeezed and pulled in the same direction as the waves travel

7. Primary Waves (P-waves)
P-waves can travel through Earth’s surface, mantle, and inner and outer cores
P-Wave – travels through the mantle and core

8. Primary Waves (P-waves)

9. Secondary Waves (S-waves)
Second-fastest seismic waves (travel slower than p-waves)
Rocks moves perpendicular (right angles from) the direction the waves travel

10. Secondary Waves (S-waves)
S-waves can travel through Earth’s surface and mantle, but CANNOT pass through the liquid outer core
S-Wave – travels through the mantle, but can’t travel through the core

11. P-Wave – wave moving to the right, rocks moving to the right
Wave Direction
P-Wave – wave moving to the right, rocks moving to the right
S-Wave – wave moving to the right, rocks moving at right angles (up and down)

12. Surface Waves (L-Waves)
Slowest seismic waves
Rocks move in two directions (both vertically and horizontally)
Only travel along Earth’s surface (crust)
Most destructive of all seismic waves

13. Locating an Epicenter
An earthquake occurs, but where did it originate?
There are recording stations all over the world measuring seismic activity

14. Locating an Epicenter
Seismometer – instrument used to measure seismic waves

15. Locating an Epicenter Seismogram – the printout from a seismometer
Which waves (P, S, or L) would show up first on a seismogram?
___-waves, because they’re the ________ P
fastest

16. Locating an Epicenter
A seismogram detects P-waves, followed by S-waves
The time between them indicates the distance between the recording station and the epicenter
The longer the time, the farther away the epicenter

17. Locating an Epicenter Blue lines = primary waves
Red lines = secondary waves

18. Locating an Epicenter
You’re in the middle of a thunderstorm. 1) The lightning flashes, and you immediately hear thunder. 2) The lightning flashes, you count 1,2,3,4,5 and then you hear the thunder. Which storm is closer to you? How can you tell?

19. 100m race 800m race What is the shorter race?
Which race has closer results?
800m race

20. Locating an Epicenter
Scientists know how far away the epicenter is, but they don’t know its exact location
They draw a circle around the recording station

21. Locating an Epicenter
They gather information from three recording stations and see where the three circles intersect (that’s where the epicenter is located)
This is called triangulation

22. Magnitude More than one million earthquakes happen each year
However, 90% of them are not felt/cause little damage
Magnitude – amount of energy released during an earthquake

23. Magnitude
Richter Scale – measures the size of the seismic waves and the energy released
Ranges from (minor to catastrophic)
Ex: Haiti 2010 – 7.0
Ex: Japan 2011 – 9.0

26. Mercalli Simulator

27. Magnitude The higher the magnitude, the greater the damage
Some of the most common hazards during an earthquake are structural damage and tsunamis

28. Tsunami Reenactment https://www.youtube.com/watch?v=mZtYDbTbyB4
Liquefaction

29. Earthquake Hazards
Tsunamis can cause complete destruction of coastal areas
Tsunamis can travel the entire distance of an ocean in only a few hours

31. Locating an Epicenter Lab
Working individually
Example problem (follow along)
Hints:
Y-Axis: each square = 20 seconds
X-Axis: each square = 200 km

32. Venn Diagram Overview Chocolate Ice Cream Vanilla Ice Cream Brown
Sweet
Cold
White
Chocolate Ice Cream
Vanilla Ice Cream