1. Earthquakes Earthquakes occur along faults. 2.1 2.2
CHAPTER
Earthquakes
the BIG idea
Earthquakes release stress that has built up in rocks.
2.1
Earthquakes occur along faults.
2.2
Earthquakes release energy.
2.3
Earthquake damage can be reduced.
CHAPTER OUTLINE

2. Earthquakes occur along faults.
2.1
Earthquakes occur along faults.
Normal faults form as rocks are pulled apart.
fault
stress
earthquake
SECTION
OUTLINE

3. Earthquakes occur along faults.
2.1
Earthquakes occur along faults.
Normal faults form as rocks are pulled apart.
Reverse faults form as rocks are pushed together.
fault
stress
earthquake
SECTION
OUTLINE

4. Earthquakes occur along faults.
2.1
Earthquakes occur along faults.
Normal faults form as rocks are pulled apart.
Reverse faults form as rocks are pushed together.
fault
Strike-slip faults form as rocks are pushed horizontally in opposite directions.
stress
earthquake
SECTION
OUTLINE

5. 2.1 fault Earthquakes occur along faults.
stress
A fracture in Earth’s lithosphere along which blocks of rock move past each other.
earthquake
KEY CONCEPT
SUMMARY

6. 2.1 stress Earthquakes occur along faults.
The force applied by an object pressing on, pulling on, or pushing against another object.
earthquake
KEY CONCEPT
SUMMARY

7. 2.1 earthquake Earthquakes occur along faults.
stress
A shaking of the ground caused by the sudden movement of large blocks of rocks along a fault.
earthquake
KEY CONCEPT
SUMMARY

8. Earthquakes release energy.
2.2
Earthquakes release energy.
focus
epicenter
seismic wave
focus
epicenter
seismograph
Seismic waves move out from the focus in all directions.
SECTION
OUTLINE

9. 2.2 seismic wave Earthquakes release energy.
focus
The vibrations caused by an earthquake.
epicenter
seismograph
KEY CONCEPT
SUMMARY

10. 2.2 focus Earthquakes release energy.
seismic wave
focus
focus
In an earthquake, the point underground where the rocks first begin to move.
epicenter
seismograph
KEY CONCEPT
SUMMARY

11. 2.2 epicenter Earthquakes release energy.
seismic wave
epicenter
focus
The point on Earth’s surface directly above the focus of an earthquake.
epicenter
seismograph
KEY CONCEPT
SUMMARY

12. 2.2 seismograph Earthquakes release energy.
seismic wave
seismograph
focus
An instrument that constantly records ground movements.
epicenter
seismograph
KEY CONCEPT
SUMMARY

13. Earthquake damage can be reduced.
2.3
Earthquake damage can be reduced.
A powerful earthquake releases more energy and causes more shaking of the ground than does a weak earthquake.
aftershock
liquefaction
Magnitude
0–3.9
Very Minor to Minor
4.0–4.9
Light
5.0–5.9
Moderate
6.0–6.9
Strong
7.0–7.9
Major
Effects Near Epicenter
8.0 and above
Great
major to total destruction
rarely noticed
slight damage
some structures damaged
major damage to structures
some well-built structures destroyed
tsunami
SECTION
OUTLINE

14. Earthquake damage can be reduced.
2.3
Earthquake damage can be reduced.
aftershock
An area’s risk of earthquakes can be predicted.
kilometers
miles
liquefaction
tsunami
SECTION
OUTLINE

15. Earthquake damage can be reduced.
2.3
Earthquake damage can be reduced.
aftershock
Structures can be designed for greater safety in an earthquake.
liquefaction
tsunami
SECTION
OUTLINE

16. 2.3 aftershock Earthquake damage can be reduced.
liquefaction
A smaller earthquake that follows a more powerful earthquake in the same area.
tsunami
KEY CONCEPT
SUMMARY

17. 2.3 liquefaction Earthquake damage can be reduced.
aftershock
liquefaction
liquefaction
A process in which the shaking of ground causes loose, wet soil to act like a liquid.
tsunami
KEY CONCEPT
SUMMARY

18. 2.3 tsunami Earthquake damage can be reduced.
aftershock
tsunami
liquefaction
A water wave caused by an earthquake, volcanic eruption, or landslide.
tsunami
KEY CONCEPT
SUMMARY

19. 2.1 Earthquakes occur along faults. I. Earthquakes occur along faults.
A. Rocks move along faults.
stress
B. Faults are classified by how rocks move.
earthquake
1. Normal Faults
2. Reverse Faults
3. Strike-Slip Faults
KEY CONCEPT
SUMMARY

20. Earthquakes release energy.
2.2
Earthquakes release energy.
II. Earthquakes release energy.
seismic wave
A. Energy from earthquakes travels through Earth.
focus
epicenter
1. Waves and Energy
seismograph
2. Primary Waves
3. Secondary Waves
4. Surface Waves
B. Seismic waves can be measured.
1. Using Seismographs
2. Locating an Earthquake
KEY CONCEPT
SUMMARY

21. Earthquake damage can be reduced.
2.3
Earthquake damage can be reduced.
III. Earthquake damage can be reduced.
aftershock
A. Earthquakes can cause severe damage and loss of life.
liquefaction
1. Earthquake Magnitude
tsunami
2. Damage from Earthquakes
3. Damage from Tsunamis
B. Scientists work to monitor and predict earthquakes.
C. Structures can be designed to resist earthquake damage.
KEY CONCEPT
SUMMARY