Chapter 12 Study Notes

Earthquakes

1

• A ____ wave is a seismic wave that travels through the _____ of the earth.

– body– interior

2

• A _______ is a small earthquake that may precede a ______ earthquake.

– foreshock– larger

3

• A modern _______ consists of _____ sensing devices.

– seismograph– three

4

• A ______ ______ is an area in which strong earthquakes have occurred in the ______.

– seismic– gap– past

5

• A ______ displays earthquake motion ________ by a seismograph.

– seismogram– recorded

6

• A _______ is an instrument that records the ground _______.

– seismograph– vibrations

7

• A __________ is an area where no direct ______ _____ from a particular earthquake can be detected.

– shadow zone– seismic– waves

8

• A ______ wave is a seismic wave that travels along the _______ of the earth.

– surface– surface

9

• A ______ is a large ocean _____ that forms after a volcanic eruption, underwater earthquake, or landslide.

– tsunami– wave

10

• As tsunamis move toward shore the waves _______ in _____.

– increase– height

11

• Before and after an earthquake you should stay _______ and follow ________.

– cautious– instructions

12

• During a _____ earthquake, buildings may _____ or _______.

– major– sway– collapse

13

• Earth’s interior affects the _____ and _______ of seismic waves.

– speed– direction

14

• Earthquake _______ is _________.– prediction– unreliable

15

• Earthquakes generally occur at _____ _______ where stress on rocks is the ________.

– plate– boundaries– greatest

16

• _______ ________is the ______ return of deformed rock to its ________ shape.

– Elastic– rebound– sudden– undeformed

17

• If you are ______ during an earthquake, you should crouch under _____.

– indoors– desk

18

• _____ is the amount of _______ caused by an earthquake.

– Intensity– damage

19

• Intensity ____ on the modified Mercalli scale is described as causing _____ __________.

– XII– total– destruction

20

• ________ is a measure of the ______ of an earthquake.

– Magnitude– strength

21

• P _______ are the ______ body waves.– waves– fastest

22

• P waves can travel through ______, ______, and _______.

– solids– liquids– gases

23

• P waves travel _______ through very _____ and not easily _______ materials.

– fastest– rigid– compressed

24

• S waves can only travel through ______.– solids

25

• Scientists find the _______ of an earthquake by comparing the ______ times of P waves and S waves at _____ or more seismograph stations.

– epicenter– arrival– three

26

• Scientists study ______ ______, ____ ______, and _______ in order to predict earthquakes.

– seismic– gaps– rock– changes– foreshocks

27

• The _______ of an earthquake is the point on Earth’s _______ directly above the earthquake’s focus.

– epicenter– surface

28

• The ______ ______ of an earthquake occurs at the _____.

– first– motion– focus

29

• The _______ _______ scale measures the _________ of an earthquake.

– modified– Mercalli– intensity

30

• The moment magnitude scale measures the ________ of an earthquake by the _____ size and the ______ that the fault blocks move.

– magnitude– fault– distance

31

• The _______ _______ scale measures the ________ of large earthquakes the most ________.

– moment– magnitude– magnitude– accurately

32

• The Richter scale is based on ________.– magnitude

33

• The Richter scale measures the _____ of an earthquake using ______ ______.

– magnitude– ground– motion

34

• _______ _______, ________, and undersea ________ may all cause a tsunami.

– Volcanic– eruptions– earthquakes– landslides

35

• When seismologists record ______ times of P waves and S waves at three or more seismograph stations, they are looking for the earthquake’s ________.

– arrival– epicenter

36

• You can prepare for an earthquake by gathering _____, _____, _______, and a portable _____.

– food– water– flashlights– radio

The End