Earthquakes
April-18-12
8:19 PM
As tectonic plates move, stress builds up
at the boundaries. When the plates can no
longer handle the stress, it releases in the
form of an earthquake.
There are several locations we have to be
aware of:
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aware of:
Epicentre = point on Earth's surface
directly above focus
Focus = location where earthquake begins
Example: Desk
Energy from earthquakes travel in the
form of seismic waves.
Seismic waves are classified into four
different categories:
P-waves = fastest, travels through solids,
liquids, and gases, forward-and-back
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liquids, and gases, forward-and-back
motion
S-waves = second fastest, travels only
through solids, up-and-down motion
L-waves = third fastest, travels along the
surface, sideways motion
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R-waves = slowest, travels along the
surface, rolling motion
Example: Slinky
1.
Example: Students
Homework
Read 526-531
Questions 1-3 on p. 531
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