Name: 
 

8th Grade Plate Tectonics, Earthquakes and Volcanoes


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The seafloor spreading theory was proposed by ____
a.
Alfred Wegener.
c.
Abraham Ortelius.
b.
Harry Hess.
d.
Carl Sagan.
 

 2. 
As Earth’s plates move apart at some boundaries, they collide at others, forming ____
a.
mountains and volcanoes.
c.
strike-slip faults.
b.
ocean basins.
d.
both a and b.
 

 3. 
The youngest rocks in the ocean floor are located at the mid-ocean ____
a.
volcanoes.
c.
trenches.
b.
basins.
d.
ridges.
 

 4. 
The results of plate movement can be seen at ____
a.
rift valleys.
c.
plate centers.
b.
plate boundaries.
d.
both a and b.
 

 5. 
The ____ are forming where the Indo-Australian plate collides into the Eurasian plate.
a.
Andes mountain range
c.
Himalayas
b.
Rocky Mountains
d.
Appalachian Mountains
 

 6. 
The presence of the same ____ on several continents supports the idea of continental drift.
a.
fossils
c.
neither a nor b
b.
rocks
d.
both a and b
 

 7. 
Continental drift occurs because of ____
a.
seafloor spreading.
c.
magnetic reversal.
b.
Pangaea.
d.
earthquakes.
 

 8. 
The cycle of heating, rising, cooling, and sinking is called a ____
a.
subduction zone.
c.
convection current.
b.
convergent boundary.
d.
conduction current.
 

 9. 
Oceanic plates are pushed down into the upper mantle in ____
a.
convection currents.
c.
strike-slip faults.
b.
subduction zones.
d.
divergent boundaries.
 

 10. 
The hypothesis that continents have moved slowly to their current locations is called ____
a.
continental drift.
c.
magnetism.
b.
continental slope.
d.
convection.
 

 11. 
Plates move apart at ____ boundaries.
a.
convergent
c.
divergent
b.
transform
d.
magnetic
 

 12. 
Ocean floor rocks are ____ continental rocks.
a.
more eroded than
c.
younger than
b.
older than
d.
the same age as
 

 13. 
The alignment of iron-bearing minerals in rocks when they formed reflects the fact that Earth’s ____ has reversed itself several times in its past.
a.
magnetic field
c.
asthenosphere
b.
core
d.
gravity
 

 14. 
The lack of an explanation for continental drift prevented many scientists from believing a single supercontinent called ____ once existed.
a.
Glomar
c.
Pangaea
b.
Glossopteris
d.
Mesosaurus
 

 15. 
Scientists aboard the Glomar Challenger added to the evidence for the theory of seafloor spreading by providing ____
a.
high altitude photos of existing continents.
b.
samples of plant life from different locations.
c.
samples of rock from different locations.
d.
direct measurements of the movement of continents.
 

 16. 
Where plates slide past one another, ____ occur.
a.
volcanoes
c.
island arcs
b.
earthquakes
d.
ocean trenches
 

 17. 
The places between plates moving together are called ____
a.
divergent boundaries.
c.
strike-slip faults.
b.
convergent boundaries.
d.
lithospheres.
 

 18. 
Seafloor spreading occurs because ____
a.
new material is being added to the asthenosphere.
b.
earthquakes break apart the ocean floor.
c.
sediments accumulate on the ocean floor.
d.
hot, less-dense material below Earth’s crust is forced upward toward the surface.
 

 19. 
Studying the ocean floor, scientists found rocks showing magnetic ____
a.
weakening.
c.
bonds.
b.
reversal.
d.
poles.
 

 20. 
Molten rock inside Earth is ____.
a.
lava
c.
tephra
b.
magma
 

 21. 
Subduction takes place at a ____ plate boundary.
a.
convergent
c.
transform
b.
divergent
 

 22. 
The Richter scale measures ____.
a.
intensity
c.
magnitude
b.
duration
 

 23. 
A broad, shallow volcano with lava sides is a ____ volcano.
a.
shield
c.
cinder cone
b.
composite
 

 24. 
Tectonic plates are moved around by ____.
a.
seismic waves
c.
convection currents
b.
nuclear reactions
 

 25. 
____ waves are the slowest and largest of the seismic waves and cause most of the destruction during an earthquake.
a.
Primary
c.
Surface
b.
Secondary
 

 26. 
Most earthquakes and volcanic eruptions occur ____.
a.
at the center of the plates
c.
at plate boundaries
b.
near the equator
 

Completion
Complete each statement.
 
 
Fill in the blanks using the terms below. Some terms will not be used.
earthquakeepicenterfaultfocusRichter
lithospheremagmamagnituderiftssurface waves
seismic wavesseismographsubductionlavatsunami
volcanoesintensityP-wavesseismic safeS-waves
Modified Mercali
 pyroclastic flow 
 

 27. 
____________________ are cone-shaped mountains that eject lava and other materials.
 

 

 28. 
A ____________________ is the surface of a break in a section of rocks.
 

 

 29. 
Another name for earthquake waves is ____________________.
 

 

 30. 
The place inside Earth where the energy in an earthquake is centered is the ____________________.
 

 

 31. 
The instrument used to record earthquake activity is a ____________________.
 

 

 32. 
The ____________________ of an earthquake is the point on the surface of Earth directly above the focus.
 

 

 33. 
The ____________________ of an earthquake is based on the amplitude of the seismic waves.
 

 

 34. 
An undersea earthquake may produce a ____________________.
 

 

 35. 
Buildings constructed to withstand most earthquakes are said to be ____________________.
 

 

 36. 
____________________ is magma that has flowed onto Earth’s surface.
 

 

 37. 
The ____________________ is divided into about 13 major plates.
 

 

 38. 
____________________ are long cracks produced at divergent plate boundaries.
 

 

 39. 
The ____________________ scale measures the magnitude of an earthquake.
 

 

 40. 
The seismic waves that do the most damage to structures and property during an earthquake are ____________________.
 

 

 41. 
An avalanche of glowing rocks flowing on a cushion of hot gases is called a(n) ____________________.
 

 

Short Answer
 

 42. 
Compare and contrast divergent, convergent, and transform plate boundaries.
 

 43. 
Describe how convection currents might be the cause of plate tectonics.
 

 44. 
Why are new ideas often rejected, and what is needed before new ideas should be accepted?
 

 45. 
What is the difference between a convergent and a divergent plate boundary?
 

 46. 
What happens to warmer material in a convection current?
 

 47. 
What observation led Albert Wegener to develop the hypothesis of continental drift?
 

 48. 
Which part of Earth’s structure is about 100 km thick?
 

 49. 
How were the Andes mountain range, the Himalayas, and the islands of Japan formed alike?
 

 50. 
How were the Andes mountain range, the Himalayas, and the islands of Japan formed differently?
 

 51. 
What causes new material to form at a mid-ocean ridge on the ocean floor?
 

 52. 
Why are there few volcanoes in the Himalayas?
 

 53. 
Glacial deposits often form at a high latitude near the poles. Explain why glacial deposits have been found in Africa.
 

 54. 
Why would the fossil of an ocean fish found on two different continents NOT be good evidence of continental drift?
 

 55. 
Explain how research from the Glomar Challenger helped scientists support the theory of seafloor spreading.
 

 56. 
Since new crust is constantly being added, why does Earth’s surface not keep expanding?
 

 57. 
Name the three kinds of faults and describe each of them.
 

 58. 
How are tectonic plates related to earthquakes and volcanoes?
 

 59. 
P-waves can pass through almost all materials, but S-waves cannot pass through liquid. Scientists have noted that when measuring seismic waves from earthquakes on the other side of the planet, only P-waves are recorded in some areas. What could you infer about the center of Earth from these observations?
 

 60. 
How is stretching a rubber band until it breaks like Earth’s crust during an earthquake?
 

 61. 
In an aerial view of California, you can trace the San Andreas fault all along the coast of California. What kind of fault is the San Andreas fault?
 

 62. 
The Hawaiian Islands are formed from a series of volcanoes. The next Hawaiian island, Loihi, is already 3,000 meters above the ocean floor, although it is still nearly 1,000 meters below the surface of the ocean. What tectonic plate feature is forming the new island of Loihi?
 

 63. 
Describe tectonic plates using the terms crust, upper mantle, lithosphere, and motion.
 

 64. 
Name two precautions you should take before an earthquake. Name two precautions you should take after an earthquake.
 

 65. 
List three ways volcanoes can be damaging to humans and the environment.
 

Matching
 
 
Match each term with the description below.
a.
lithosphere
i.
convergent boundary
b.
mantle
j.
subduction zone
c.
plate tectonics
k.
asthenosphere
d.
seafloor spreading
l.
strike-slip fault
e.
convection current
m.
transform boundary
f.
continental drift
n.
divergent boundary
g.
Pangaea
o.
crust
h.
magnetometer
p.
plates
 

 66. 

 plasticlike layer of Earth’s surface below the lithosphere
 

 67. 

 cycle of heating, rising, cooling, and sinking
 

 68. 

 theory that states that Earth’s crust and upper mantle are broken into sections, which move around on a special layer of the mantle
 

 69. 

 area where an oceanic plate goes down into the mantle
 

 70. 

 plate boundary that occurs when two plates slide past one another
 

 71. 

 place where two plates move together
 

 72. 

 rigid layer of Earth’s surface made up of the crust and a part of the upper mantle
 

 73. 

 sensing device that detects magnetic fields, helping to confirm seafloor spreading
 

 74. 

 one large landmass hypothesized to have broken apart about 200 million years ago into continents
 

 75. 

 hypothesis that the continents have moved slowly to their current locations
 

 76. 

 boundary between two plates that are moving apart
 

 77. 

 sections of Earth’s crust and upper mantle
 

 78. 

 largest layer of Earth’s surface, composed mostly of silicon, oxygen, magnesium, and iron
 

 79. 

 outermost layer of Earth’s surface
 

 80. 

 where rocks on opposite sides of a fault move in opposite directions or in the same direction at different rates
 
 
Choose the correct category for each item.
a.
related to earthquakes
b.
related to volcanoes
c.
related to both earthquakes and volcanoes
 

 81. 

 ash and mudslides
 

 82. 

 seismic safe construction techniques
 

 83. 

 hot spots
 

 84. 

 magnitude
 

 85. 

 elastic rebound
 

 86. 

 rift
 

 87. 

 tsunami
 

 88. 

 tephra
 

 89. 

 tectonic plates
 



 
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