Name
Class
Date
Skills Worksheet
Concept Review
In the space provided, write the letter of the description that best matches the
term or phrase.
______ 1. seismic gap
______ 2. Richter scale
______ 3. body wave
______ 4. tsunami
______ 5. modified Mercalli scale
______ 6. surface wave
a. an instrument used for detecting and
recording vibrations in the ground
b. a measurement of earthquake strength
based on the size of the area of the fault
that moves
c. a scale expressing earthquake intensity
d. a wave that travels through the body of
a medium
______ 7. seismograph
e. a scale that measures the ground
motion from earthquakes
______ 8. foreshock
f. the sudden return of deformed rock to
its undeformed state
______ 9. elastic rebound
______ 10. moment magnitude
g. a wave that travels along the surface of
a body, not through the middle
h. a fault area where few quakes have
occurred recently, but where strong
quakes have occurred in the past
i. a little earthquake that precedes a
larger one
j. a giant wave that can form after an
undersea earthquake
In the space provided, write the letter of the answer choice that best completes
each statement or best answers each question.
______ 11. What can happen to tall buildings during an earthquake?
a. They can crack and implode.
b. The windows can blow out from the inside.
c. Nothing usually happens.
d. They can sway and even tip over.
______ 12. If you are inside during an earthquake,
a. lie down in an open area.
b. call 911.
c. get outside as quickly as possible.
d. stand in a doorway or crouch under a desk.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Earth Science
1
Earthquakes
Name
Class
Date
Concept Review continued
______ 13. Why do seismic waves speed up at about 30 km beneath the surface
of continents?
a. because Earth’s mantle is denser than the crust
b. because of Earth’s magnetic field
c. because Earth’s crust is denser than the mantle
d. because of the force of gravity
______ 14. Why do earthquakes usually occur at plate boundaries?
a. because stress on the rocks is least at the boundaries
b. because of gravity pushing down on the plates
c. because the stress on the rocks of the plates is greatest at
the boundaries
d. because of the magnetic qualities of the plates
______ 15. If you are in a car during an earthquake, you should
a. stop away from structures that might collapse.
b. get inside a building.
c. get out of the car.
d. drive away quickly.
______ 16. When an earthquake occurs,
a. run as fast as you can.
b. stay calm.
c. get inside a building.
d. panic.
______ 17. How do scientists find the distance to an epicenter?
a. by analyzing departure times of P waves and S waves
b. by graphing P waves and Q waves
c. by measuring distances in kilometers
d. by analyzing arrival times of P waves and S waves
______ 18. Scientists monitor natural gas seepage from rocks because
a. it may cause earthquakes.
b. it may mean trouble.
c. it may indicate seismic activity.
d. it may indicate the presence of oil.
______ 19. Where does the first motion of an earthquake occur?
a. at the focus
b. at the center
c. in the fault zone
d. in the crust
______ 20. What is another name for a P wave?
a. a proper wave
b. a secondary wave
c. a tidal wave
d. a primary wave
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Earth Science
2
Earthquakes
ANSWER KEY
Answer Key
Concept Review
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
H
E
D
J
C
G
A
I
F
B
D
D
A
C
A
B
D
C
A
D
Critical Thinking
13.
14.
15.
16.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
D
A
B
C
C
B
D
C
A
Answers may vary. Sample answer:
Dating organic matter in the soil at the
site of a fault excavation where a past
disturbance was detected could lead to
an accurate dating of that disturbance.
11. Answers may vary. Sample answer: The
main assumption is that there were
earthquakes and seismic activity at the
site in the past. This assumption can be
made because faults are known to be
the sites of seismic activity and earthquakes over time.
12. Answers may vary. Sample answer:
From such studies, recurring patterns
of earthquake location, magnitude, and
17.
18.
19.
timing might emerge. The idea that such
patterns would continue into the future
would allow predictions to be made.
Answers may vary. Sample answer:
Disagree. One of the most powerful earthquakes in recorded history
occurred in the middle of the continental United States at New Madrid,
Missouri, far from any active plate
boundaries.
Answers may vary. Sample answer:
Agree. A building built on loose soil or
loose rock is much more likely to be
damaged in an earthquake than one
built on solid ground. The loose soil
and rock vibrate like jelly, causing the
building to sway.
Answers may vary. Sample answer:
Agree. The vibrations of earthquakes
with deeper foci are usually relatively
weak by the time they reach Earth’s
surface. The vibrations of earthquakes
with shallow foci still have a lot of
energy left when they reach the surface.
Answers may vary. Sample answer:
Disagree. There are very few examples
of foreshocks accurately predicting
an earthquake within a timeframe that
allowed people to take precautions.
Answers may vary. Sample answer:
Disagree. A few simple rules can help
to prevent death, injury, and property
damage. People who live near active
faults should have emergency food,
radios, and lights on hand. During an
earthquake, knowing what positions
are safe and when to get to them can
protect people. Being alert for hazards
such as fires and downed power lines
can help after an earthquake.
Answers may vary. Sample answer:
The scientist has found a seismic gap.
Because the gap is along a fault and
hasn’t had much recent activity, it is
possible that this area may be the site
of a future earthquake, as pressure
builds up in the rocks.
Answers may vary. Sample answer: If
the arrival times of the P waves and S
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Holt Earth Science
54
Earthquakes