Forces in Earth’s Crustn Lesson 1
Understanding Main Ideas
Use the diagrams below to complete items 1–9 .
Diagram A
1. Type of Fault: _______________
2. Stress Force: _______________
3. Movement Along Fault: _______________
Diagram B
4. Type of Fault: _______________
5. Stress Force: _______________
6. Movement Along Fault: _______________
Diagram C
7. Type of Fault: _______________
8. Stress Force: _______________
9. Movement Along Fault: _______________
Building Vocabulary
Write a definition for each of these terms on a separate sheet of paper.
10. shearing
11. plateau
Forces in Earth’s Crust Lesson 1
Each picture below shows how an earthquake changed the land surface at a fault.
Examine the pictures carefully. Decide what kind of fault is shown in each. Then explain
how movement along the fault caused the changes you see. Write your answers in the
spaces provided.
1. Fault 1 __________________________________________________________________________
2. Fault 2 __________________________________________________________________________
3.
Fault 3
Earthquakes and Seismic Waves
Lesson 2
If the statement is true, write true. If the statement is false, change the underlined word
or words to make the statement true.
1. _____________ The shaking and trembling that results from movement of rock
beneath Earth’s surface is called an earthquake.
2. _____________ Earthquakes are caused by the forces of mountain movement.
3. _____________ The epicenter of an earthquake is below the focus.
4. _____________ P waves can become surface waves when they reach Earth’s
surface.
5. _____________ The Modified Mercalli scale rates the amount of damage from
an earthquake.
6. _____________ To locate the epicenter of an earthquake, geologists need data
from two or more seismographs.
Fill in the blank to complete each statement.
7. Seismic waves are _____________ that are similar to sound waves.
8. The _____________ of an earthquake is the point where rock under stress
begins to break or move.
9. The seismic waves that move fastest are _____________.
10. Geologists use the moment magnitude scale to rate the total _____________
released by an earthquake.
Monitoring Earthquakes Lesson 3
Read the passage and look at the diagram. Then use a separate sheet of paper to answer
the questions that follow the diagram.
Earthquake Probability
This combined map and bar graph shows the probability of earthquakes in different areas along the san
Andreas fault. Probability is a measure of how likely it is that some event will happen in a given time.
A probability near 100 percent means that an event in very likely to happen. A probability near zero
percent means that an event is very unlikely to happen.
1. Which area has the highest probability of an earthquake?
2. What is the probability of an earthquake in the North Coast area?
3. The fault section between the Santa Cruz Mountains and Parkfield
has a very low probability. Geologists know that this area has
experienced very little damaging seismic activity in the past. They
also found that the blocks of rock in this section move slowly and
continually. Why would slow, continual movement lead geologists to
give the section a low probability?
4. What can you infer about why the probability of an earthquake is so
high in the Parkfield area?