Seismic Waves

1
Seismic Waves
The source of an earthquake is called the focus
and the epicenter is the point on Earths surface
directly above the focus. Seismic waves originate
at the focus and travel outward in all
directions. These energy waves are
classified as
1) Body Waves
2) Surface Waves
Reference Tarbuck and Lutgens Pages 159 -
161
2
Body Waves
Two types of body waves
3
Body Waves
4
Body Waves
5
Surface Waves
Two types of surface waves
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Surface Waves
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Surface Waves
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Seismograph
9
Seismograph and Seismogram
10
Sample Problem
Contrast the characteristics of Primary and
Secondary waves.
Answer P - wave Push - pull waves which
vibrate in the same direction in which they move.
Fastest earthquake wave and is the first to
arrive at seismograph stations. Pass through all
states of matter, solids, liquids, and gases. S -
wave Shake the particles which cause them to
vibrate in a perpendicular direction to their
motion. Slower than P - wave and is the second
earthquake wave to arrive at seismic stations.
Pass only through solids.