Seismic Waves and Earth’s Interior
Environmental Science
Name: ______________________________________ Period: __________ Date: ___________________
Essential Question: How are seismic waves used in determining the structure and composition
of Earth’s interior?
1. What do you call the study of earthquake? ( p. 500)
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2. Why do seismologists study seismic waves? ( p. 500, 503-504)
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3. What is the instrument that detect and measure seismic waves? ( p. 500)
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4. What is a seismogram? ( p. 500)
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5. What is a seismic facility? ( p. 501)
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6. Study Figure 19-9 and answer the questions.
a. Which is faster ? Encircle one
P-waves
S-waves
b. How many minutes did it take for P-waves to reach 3000 km? _______________________
c. How many minutes did it take for S-waves to reach 3000 km? _______________________
7. Where do most of what we know about the earth’s interior come from? ( p. 502)
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8. How do scientist use seismic waves to know the interior of Earth? ( p. 502)
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9. To understand how scientist use seismic waves ( P and S waves) to learn about Earth’s interior.
Study and draw Figure 19-10, p 503. Draw the bending of the arrows accurately.
Figure 19-10
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10. Observe how the P and S waves ( seismic waves) are refracted when they travel inside Earth.
Explain how scientist get clues from seismic wave refraction to predict the interior of Earth.
( p. 502-503, Fig. 19-10 Think!)
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11. What is refraction? ( p. 414, 749, observe the direction of waves. Do they move straight? Think!)
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12. What is the lithosphere? ( p. 8)
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What are the two kinds of Earth’s crust? ( p. 8)
_________________________ is the layer made mostly of granite.
_________________________ is the layer made mostly of basalt. Basalt is heavier than granite.
13. What PERIDOTITE? ( P. 504)
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14. Study Figure 19-11 in your textbook p. 504, and answer the following questions.
The Earth's Crust is like the skin of an apple. It is very thin in comparison to the other three
layers. The crust is only about 3-5 miles (8 kilometers) thick under the oceans(oceanic crust) and
about 25 miles (32 kilometers) thick under the continents (continental crust)
a. Which is thicker between the two types of Earth’s crust? (read the
paragraph above)
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b. How thick is the lithosphere ( crust and upper mantle)?
Approximately ________________________________ kilometers
c. What kind of rocks make up the lithosphere?
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d. What kind of rock is the asthenosphere made of?
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e. How thick is the asthenosphere?
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15. Scientist also learn about the composition of Earth’s interior by examining meteorites. How
can objects from space help scientist learn more about Earth’s interior? ( p. 504, Think!)
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