1. Warm-up
Take out your vocabulary cards and place them on the table where I can see them.
What are the three types of plate boundaries and how are they different from each other? (you can include a picture to help show the difference between the 3 types!)
Describe what happens when you try to bend a pencil too far?

2. Earthquakes!
Anatomy: structural makeup especially of an organism or any of its parts *

3. Did you know?
Due to west coast building codes it is highly unlikely that the Golden Gate Bridge or the Space Needle will collapse during an earthquake.

4. OBJECTIVE
Describe the anatomy of an earthquake and relate earthquakes to the different types of plate boundaries.

5. Haiti Earthquake example: Haiti, on January 12, 2010
How severe was this earthquake? 7.0 magnitude
What happens: What happens with a 7.0 magnitude earthquake?
What was the actually happened in Haiti?
Analysis questions:
1. What type plate boundary motion would cause this 7.0 magnitude earthquake to occur?
2. What were some of the differences you saw before and after the earthquake?
What happens:
What actually happened? *

6. Japan Earthquake example: Japan, on March 11, 2011
How severe was this earthquake?
What happens: What happens during a 9.0 magnitude earthquake?
What actually happened in Japan?
Analysis questions:
What are the differences you saw between the 9.0 (Japan) and the 7.0 magnitude (Haiti) earthquake?
Why do you think the earthquake caused the tsunami and nuclear plant meltdown in Japan?
What happens:
What actually happened? *

7. Washington D.C. Earthquake example: Washington DC, on August 23, 2011.
How severe was this earthquake?
What happens: What happens during a 5.8 magnitude earthquake?
What actually happened: What actually happened Part 2 in D.C.?
Analysis questions:
The epicenter (center) of this earthquake was in Virginia, why do you think it was felt in DC?
What do you notice is the difference between larger magnitude earthquakes (Japan and Haiti) and smaller magnitude earthquakes (DC)? Based on these observations, what you think magnitude means?

8. Hayward Fault in California!
1. What caused this fault line?
2. What could occur on this fault line?

9. Did you know?
California does NOT hold the record for the most earthquakes in the US.
Alaska is #1
Oklahoma is #2
California is #3!!!

10. Re-Loop! What type of plate boundary causes an Earthquake? Why?
Does this type of plate boundary destroy, create, or neither destroy or create lithosphere?
onment-natural-disasters/earthquakes/earthquake-101/
While watching the video- answer the questions that are on your guided notes.

11. What is an earthquake?
An earthquake is the shaking of the ground due to the movements of tectonic plates (in what layer of the earth are the tectonic plates? _____________)

12. What Causes Earthquakes?
A fault is a break in the Earth’s crust where plates slide, push or pull against each other.
Along the fault stress builds up until the rocks finally move.

13. Parts of an Earthquake
The focus of an earthquake is the point INSIDE the Earth where the earthquake starts.
The epicenter is the location on the surface of the Earth directly above the focus. Surface waves move outward from the epicenter.

14. Magnitudes and Energy of Earthquakes Annual Numbers of EQs
As indicated in previous slide, as magnitude increases by 1.0, ground motion changes by a factor of 10. The change in energy with magnitude is even more dramatic. A change of magnitude by 1.0 corresponds to a change in energy released by a factor of 32!
Notice the dramatic change in number of earthquakes of different sizes. Small earthquakes are MUCH more frequent than large earthquakes. However, because the energy changes by a factor of 32 with an increase of 1.0 in magnitude, large earthquakes account for most of the energy released in earthquakes. There are about 20 earthquakes of magnitude 7.0 or greater each year and these release 80% of all seismic energy.
Earthquake Energy—To rephrase, for each unit of magnitude the amplitude of the waves increases by a factor of 10, but the duration also increases, so the energy released increases by a factor of 32!
RESOURCE: See file “No. 3. How Often do Earthquakes Occur?” on website
What is the relationship between magnitude and energy released?
The magnitude depends on the amount of energy released by the earthquake. There are a million 2 magnitude earthquakes a year, but less than one 9 magnitude! *

15. Seismic intensity is affected by rock type.
A major influence on earthquake damage is the ground that buildings are built upon. In the San Francisco Bay area, soft muddy areas experience much large ground oscillations than do areas of hard bedrock. Earthquake damage tends to be high in Bay Mud areas and lower in areas underlain by bedrock.
The level of shaking is controlled by the proximity of the earthquake source to the affected region and the types of rocks that seismic waves pass through en route (particularly those at or near the ground surface).
Generally, the bigger and closer the earthquake, the stronger the shaking. But there have been large earthquakes with very little damage either because they caused little shaking or because the buildings were built to withstand that kind of shaking. In other cases, moderate earthquakes have caused significant damage either because the shaking was locally amplified, or more likely because the structures were poorly engineered.
Amplitude of oscillation
Form a hypothesis about how would you expect the houses to react during an EQ. *

16. Seismic intensity is affected by rock type.
This drawing does not show the S and P-wave arrivals on the seismogram. Rather, it shows how the seismic wave oscillates as it enters different materials.
The least damage occurs where buildings are constructed on bedrock. Note that the seismogram signal through “solid bedrock” is a high-frequency, low-amplitude.
By the time the seismic wave reaches the “well-consolidated sediment” it begins to wobble with more amplitude but less frequently.
The “poorly consolidated” sediment is even worse.
As the wave enters the “water-saturated sand and mud” the wave records a low-frequency, high-amplitude signal. It really gets rolling and can cause liquifaction [during ground shaking, some sandy, water-saturated soils can behave like liquids rather than solids. See the activity in the Exploratorium website noted below.]
Background below from
During a quake, the squeezing done by the seismic waves happens very quickly, and the water doesn’t have time to flow out of the way of the sand particles. So as the particles try to move into a denser configuration, they push on the water, causing an increase in water pressure.This increased pressure causes the forces at the contact points between the sand particles to decrease. If the water pressure is high enough, it can reduce the interparticle forces to zero, which means that the sand particles ﾒfloatﾓ away from each other. For a brief time, the sand particles are suspended in the water. This is liquefaction. The soilﾕs loss of strength occurs because thereﾕs no contact between the particles of sand.So What?
Many buildings in the San Francisco Bay Area are built on landfill, sand, or mud that can liquefy. Liquefaction caused much of the damage during the 1989 Loma Prieta earthquake. It has also been responsible for major destruction in other quakes, including Kobe, Japan, in 1995 and Mexico City in 1985.
Same magnitude, more shaking *

17. Ring of FIRE Located in the Pacific Ocean
Series of trenches, volcanic arcs and volcanic belts
90% of the world’s earthquakes
81% of the largest earthquakes

18. Group Activity
Get in your groups and work on your Plate Tectonics Guided Worksheet. I will assign roles. You have 25 minutes.

19. ELASTIC REBOUND
Along a fault, energy builds up in a rock until it breaks and releases energy.
This release of energy causes an earthquake.

20. Elastic Rebound Theory
Definition: the gradual buildup, and release of stress and strain, between tectonic plates, which leads to earthquakes.

21. Elastic Rebound Demonstration

22. Exit Ticket What is an epicenter?
Where is the focus in relation to the epicenter?
Define fault.
What is the elastic rebound theory?
Additional links to check out (for extra class time/early finishers): *