Earthquakes are caused by the movement of rock beneath Earth's surface. They are measured using seismic waves and the magnitude scale, which indicates the strength based on wave movement and fault slippage. Major earthquakes can cause damage through tsunamis, death, and collapsed buildings. There are two types of seismic waves - primary and secondary - as well as two types of body waves that travel at different speeds within the Earth. The elastic rebound theory explains that stress gradually builds up on faults until the rocks slip and cause an earthquake. The 2011 Tohoku earthquake in Japan was a magnitude 9.0 quake that caused tsunamis, loss of life and resources, and shifted GPS sensors.
2. Basic Background Information
-What is an earthquake?
The shaking that results from the movement of rock
beneath Earth’s surface .
-How are earthquakes measured?
Seismic Waves .
-What does magnitude mean?
A measurement of earthquake strength based on
seismic waves and movement along faults .
-How is magnitude measured?
Movement Magnitude Scale .
3. Damage Caused by Earthquakes
• Tsunami .
• Death .
• Damaged Nuclear Power Plants .
• Buildings Fall Apart .
4. Waves
What are earthquake waves called?
Seismic Waves .
What two types of seismic waves are there?
Primary and Secondary .
What two types of body waves are there?
Primary and Secondary .
5. Body Waves
How do P waves travel?
Stretch and compress the rock in their path through
Earth .
How do S waves travel?
Move the rock in their path up and down and side to
side .
Which move faster?
Seismic Waves .
6. Elastic Rebound
Theory of earthquakes that envisades gradual deformination of the
fault slippage until friction is overcome , when suddenly slips to
produce the earthquake .
The elastic rebound theory of earthquakes sources allows rough
prediction of the occurrence of large shallow earthquakes .
The uplift associated with earthquakes and mountain building.
Uplift of the Earth’s surface also has occurred in response to the
removal of Pleistocene ice sheets through melting and wastage
.
Elastic rebounds occur in the
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7. The Tohoku Earthquake
This quake occurred at :
2:46 p.m.
This quake occurred
East , West .
The magnitude of this quake was
9.0
8. Effects on the environment/earth
Caused the planet to rotate Quic kTime™ and a
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faster , shortening the length
of the day by about 1.0
millionths of a second .
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Tsunami .
Changed Shifts . QuickTime™ and a
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9. Effects on the People of Japan
Famine . QuickTime™ and a
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Missing People .
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Limited Resources . Quic kTime™ and a
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10. Effects on the Economy of Japan
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11. GPS Sensors
• One interesting fact about this earthquake is
that it moved several GPS sensors. This will
require …(Type answer here)
• How does elastic rebound explain this
movement?
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12. Tsunamis
• What is a tsunami?
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• How do tsunami waves appear at sea?
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• How high can tsunami waves be?
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• How fast can tsunami waves move?
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