Deck 6: Earthquakes

Question 1

How can injection of liquid wastes cause earthquakes?

A)it increases fluid pressure and reduces friction
B)it increases the rate of seismic strain accumulation
C)it causes fractures to form in metamorphic and igneous rocks
D)it increases the slip rate of the faults

Answer 1

A

Question 2

Why have 20th century earthquakes in Turkey suggested that some earthquakes beget subsequent earthquakes?

A)Two of the earthquakes were particularly strong.
B)Shoddy building construction in the most recent led to many deaths.
C)Prior to the Izmit earthquake in 1999, there had been no major quakes in more than 200 years.
D)Earthquakes have occurred in a pattern from east to west.

Answer 2

D

Question 3

How does earthquake magnitude differ from intensity?

A)Magnitude reflects energy release, while intensity reflects the amount of shaking.
B)Intensity reflects energy release, while magnitude reflects the amount of shaking.
C)The two terms are synonymous, referring simply to the size of an earthquake.
D)Magnitude is a result of the amount of shaking, which is determined by intensity.

Answer 3

A

Question 4

The epicenter of an earthquake is the point of rupture along the fault.

Question 5

Why are nearby earthquakes often described as "jolting" while distant earthquakes are described as "rolling"?

A)because high frequency waves are attenuated as they move away from the epicenter
B)because distant earthquakes only generate S-waves
C)because buildings only are destroyed by high frequency surface waves
D)because the amplitude of waves from distant earthquake are amplified by unconsolidated sediments

Question 6

Surface waves are produced by

A)faults rupturing the Earth's surface
B)the absorption of S-waves by a liquid medium
C)the reverberating effects of buildings shaking in response to high frequency P-waves
D)P- and S-waves reaching the surface

Question 7

Why might the emission of radon gas be useful in predicting earthquakes?

A)Potentially active faults emit large amounts of radon.
B)Radon gas indicates activity in the mantle, which drives plate tectonics.
C)Fracturing of the rocks allows radon to move more readily.
D)Radon gas causes seismic gaps.

Question 8

An active fault is defined as a fault that

A)is sliding at a constant, rapid pace
B)has experienced movement during Holocene time
C)has experienced movement during Pleistocene time
D)has experienced an earthquake in the last 500 years

Question 9

Most large earthquakes in the United States are interplate earthquakes.

Question 10

On what basis are Mercalli intensity values assigned to locations?

A)interpretation of seismograms
B)interpretation of the length of fault rupture
C)qualitative perceptions of and structural response to the shaking
D)proximity to the epicenter of the earthquake

Question 11

During the strain accumulation phase of the earthquake cycle

A)no seismic activity occurs
B)major seismic activity occurs
C)rocks are deformed elastically
D)the major release of elastic deformation occurs

Question 12

The 1811-1812 New Madrid earthquakes were different from most California earthquakes because

A)the New Madrid earthquakes did not occur on faults
B)the New Madrid earthquakes were centered in a plate interior
C)they were weaker than typical California earthquakes
D)they occurred on a plate boundary between the North American and Caribbean plates

Question 13

The major goal of the U.S. earthquake hazard reduction program is to

A)develop an earthquake warning system for southern California
B)reduce earthquake hazards through understanding of risks and prediction of hazards
C)federally enforce seismic building codes in active areas
D)determine the roots of human perceptions of earthquakes

Question 14

Why did the 1976 Tanshan earthquake in China deal a blow to the Chinese earthquake prediction program?

A)It occurred without foreshocks and was not predicted, unlike one the previous year.
B)A prediction was issued for a major earthquake, but the earthquake turned out to be minor.
C)No anomalous animal behavior was recorded prior to the earthquake.
D)The Chinese had never predicted an earthquake successfully, so the warnings were not heeded.

Question 15

The magnitude of an earthquake is a function of its location.

Question 16

A strike-slip fault has what type of motion?

A)horizontal
B)vertical
C)rapid
D)slow

Question 17

Buried faults are typically associated with folds in sedimentary rocks.

Question 18

Tectonic creep is the major cause of earthquakes in coastal California.

Question 19

Ground rupture occurs during an earthquake as

A)saturated sediments are liquefied
B)buildings pull away from their foundations
C)California falls into the ocean
D)a near-surface fault breaks the surface

Question 20

Tsunamis are generated by

A)rupture of faults on land
B)earthquake waves shaking the ocean floor
C)vertical displacement of ocean water
D)tides in the Pacific Ocean

Question 21

Tsunamis can cause damage thousands of miles from their source.

Question 22

The New Madrid and Charleston earthquakes were ________ earthquakes.

Question 23

________ is the transformation of saturated sediments from the solid to the liquid form.

Question 24

P-waves travel faster than surface waves.

Question 25

Bedrock, because of its strength and rapid transmittal of seismic waves, increases the amplitude of those waves.

Question 26

The process of ________ releases elastic strain during and after an earthquake.

Question 27

________ intensity is useful in rapid determination of the degree of shaking.

Question 28

A(n) ________ is an area along an active fault zone that is likely to produce large earthquakes, but has not done so recently.

Question 29

Earthquake forces are too great to be influenced by human activity.

Question 30

All earthquakes in the United States occur at plate boundaries.

Question 31

Emission of ________ gas is an occasional earthquake precursor.

Question 32

Tsunamis are only a hazard near their source.

Question 33

A(n) ________ fault is a type of reverse fault with a gentle angle of dip.

Question 34

Scientists in the country of ________ issued the first successful short-term earthquake prediction in 1975.

Question 35

A 2010 earthquake in ________ caused hundreds of thousands of deaths.

Question 36

Seismic risk maps are useful tools for short-term earthquake prediction.

Question 37

Depth of focus is an important factor in determining the intensity.

Question 38

Shake maps are used to predict where shaking is likely to occur in a future earthquake.

Question 39

The ________ magnitude is determined from the amplitude of waves recorded on seismograms.

Question 40

A(n) ________ fault has not experienced movement in the last 2 million years.

Question 41

________ involves the study of past earthquake history from trenches along faults.

Question 42

A series of earthquakes in the country of ________ in the late 20th century progressed along the fault from east to west.