Chp.5) Earthquakes

Question 1

what is an earthquake?

Answer 1

Ground shaking of Earth produced by the rapid release of
energy along faults

Question 2

earthquakes release (___), a form of energy that travels
through the Earth

Answer 2

seismic waves

Question 3

location where slippage begins

Answer 3

hypocenter (focus)

Question 4

point on Earth’s surface directly above the
hypocenter

Answer 4

epicenter

Question 5

this theory explains that earthquakes occur when rocks on either side of a fault deform and accumulate energy until their internal strength is exceeded, causing a sudden movement along the fault and releasing the accumulated energy

Answer 5

elastic rebound

Question 6

Earthquakes are often preceded by (___) and
followed by (___)

Answer 6

foreshocks and aftershocks

Question 7

Earthquakes of lesser magnitude preceding the major
earthquake

Answer 7

foreshock

Question 8

Earthquakes of lesser magnitude occurring after the major
earthquake. Can occur months or years after a major event

Answer 8

aftershock

Question 9

(___) boundaries produce some of the largest due to
immense buildup of pressure

Answer 9

convergent

Question 10

(___) boundaries can produce earthquakes along any of
its numerous branches

Answer 10

transform

Question 11

(___) boundaries produce small earthquakes

Answer 11

divergent

Question 12

study of earthquake waves

Answer 12

seismology

Question 13

seismography

Answer 13

earthquake recording instrument

Question 14

a record of seismography is called:

Answer 14

seismogram

Question 15

this type of earthquake wave has push-pull (compressional) motion, can travel through solids, liquids, gas and has the greatest velocity of all earth quake waves

Answer 15

Primary (P) waves

Question 16

this type of earthquake wave has a shake motion, travels only through solids and is slower than P waves

Answer 16

Secondary (S) waves

Question 17

this type of earthquake wave has complex motion and has the slowest velocity of all waves

Answer 17

Surface waves

Question 18

Locating the epicenter of an earthquake requires these 3 steps:

Answer 18

1.) use seismogram from 3 different locations

2.) use time-travel graph to determine distance seismic waves traveled

3.) drawing circles with the radius of distance from each seismic station, you can triangulate approximate epicenter

Question 19

A measure of the degree of earthquake shaking at a given locale
based on the amount of damage

Answer 19

intensity

Question 20

The Modified Mercalli Intensity Scale measures

Answer 20

intensity

Question 21

(___) is measured using the Richter scale

Answer 21

magnitude

Question 22

(___) is based on the amplitude of the largest seismic wave

Answer 22

magnitude

Question 23

Each unit of Richter magnitude equates to roughly a (___)-fold
energy increase

Answer 23

32

Question 24

regarding magnitude, total energy released is measured by these 3 factors

Answer 24

1.) amount of slip on the fault

2.) area of the fault that ruptured the surface

3.) strength of the rock

Question 25

4 factors the determine structural damage

Answer 25

– Intensity of the earthquake – Duration of the vibrations – Nature of the material upon which the structure rests – The design of the structure

Question 26

destruction from earthquakes results from these 3 factors

Answer 26

– Ground shaking – Wave Amplification based on ground material – Liquefaction of the ground

Question 27

landslides, fire and (___) can also result from earthquakes

Answer 27

Tsunamis

Question 28

(___) percent of energy from earthquakes in a few narrow zones

Answer 28

95

Question 29

true or false not all plate boundaries produce earthquakes

Answer 29

false all boundaries do

Question 30

Study of past earthquakes

Answer 30

Paleoseismology

Question 31

when a segment of an active fault known to produce significant earthquakes that has not slipped in an unusually long time, this is called a:

Answer 31

seismic gap

Question 32

Most of our knowledge of Earth’s interior comes from the study of (_) and (_) earthquake waves

Answer 32

P & S

Question 33

the crust can be as thin as (_) miles in oceanic regions and thick as (__) in some mountainous regions

Answer 33

5 miles 40 miles

Question 34

Upper crust composed of (___) rocks

Answer 34

granitic

Question 35

Lower crust is more akin to (___)

Answer 35

basalt

Question 36

continental crust can be up to (_) billion years old

Answer 36

4

Question 37

oceanic crust tends to be (___) millions years of age or less

Answer 37

180

Question 38

Composition of the uppermost mantle is the igneous rock (___)

Answer 38

peridotite

Question 39

outer core is composed of (___) alloy

Answer 39

iron-nickel

Question 40

(___) core behaves like a solid due to extreme pressue

Answer 40

inner