Deck 9: Earthquakes and Volcanoes

Question 1

A $\underline {\text { hypsographic }}$ curve is

A) a graph that shows the change in temperature with depth below the surface of a continent.
B) a graph that shows the change in temperature with depth below the surface of the ocean floor.
C) a generalized curve showing Earth's surface by elevation in relation to sea level.
D) a graph that shows Earth is of relatively high relief.
E) a graph that shows Earth's relief is great when compared to its diameter.

Answer 1

a generalized curve showing Earth's surface by elevation in relation to sea level.

Question 2

Terranes refer to

A) the topography of a tract of land.
B) the "lay of the land."
C) displaced and migrating pieces of Earth's crust.
D) the continental shields within each continent.

Answer 2

C

Question 3

Compared to oceanic crust, continental crust is

A) denser.
B) usually formed with less than 50 percent silica and is rich in iron and magnesium.
C) generally more complex in content and structure.
D) essentially composed of basalt.

Answer 3

C

Question 4

A topographic region that is characterized by local relief of less than 100 m (325 ft) is considered a

A) plain.
B) high tableland.
C) hill or low tableland.
D) depression.

Question 5

The variety of surface features on Earth results from

A) tectonic activity.
B) gravity.
C) weathering and erosion.
D) all of these

Question 6

Which of the following is an example of a first order of relief?

A) the Alps and Rockies
B) the Tibetan Plateau
C) the Shenandoah Valley
D) an ocean basin

Question 7

The most detailed order of relief applies to ________ order relief features.

A) first
B) second
C) third

Question 8

The concept of "orders of relief" refers to

A) the ordering of surface features based on height.
B) the ordering of surface features based on their time of origin.
C) the scale of features.
D) the rate at which stress is relieved in the crust.

Question 9

Which of the following is false regarding terranes?

A) They are smaller-scale migrating crustal pieces, i.e., microplates.
B) They may accrete onto continents and thereby increase the size of the continents.
C) They are framed by fracture zones.
D) They are very similar in composition to the continents to which they attach.
E) They can move thousands of miles from their place of origin.

Question 10

Which of the following is incorrectly matched?

A) strain - stress-induced
B) compression - shortening or folding
C) tension - stretching or faulting
D) shearing - stretching or faulting

Question 11

Vertical elevation differences in a local landscape are referred to as

A) relief.
B) an order of relief.
C) topography.
D) crust.

Question 12

The undulating form that gives Earth's surface its character and general configuration is called

A) relief.
B) an order of relief.
C) topography.
D) crust.

Question 13

Divisions among topographic regions are based on

A) arbitrary criteria regarding height or other descriptive criteria that are in common use.
B) complex statistical analyses of surface relief variation across the surface of Earth.
C) local criteria that have never been universally recognized.
D) logarithmic relationships applied to elevation.

Question 14

The average elevation of exposed land is

A) -2070 m (-6790 ft).
B) 100 m (325 ft).
C) 875 m (2870 ft).
D) 8848 m (29,028 ft).

Question 15

The average elevation of the depth of the oceans is

A) -3800 m (-12,470 ft).
B) -2070 m (-6790 ft).
C) 100 m (325 ft).
D) 875 m (2870 ft).

Question 16

Approximately what percentage of Earth's surface is exposed above sea level?

A) 18 percent
B) 29 percent
C) 49 percent
D) 62 percent

Question 17

Which of the following is an example of a third order of relief?

A) the Alps
B) a continental platform
C) the Sacramento Valley
D) the Basin and Range Province

Question 18

The average elevation of Earth's total surface is

A) -3800 m (-12,470 ft).
B) -2070 m (-6790 ft).
C) 100 m (325 ft).
D) 875 m (2870 ft).

Question 19

The nucleus of old crystalline rock in each of the principal continental masses is called a

A) basalt mass.
B) continental shield, or craton.
C) mountain mass.
D) composite zone.

Question 20

If you wanted to avoid earthquakes, which of the following areas would be the safest to live?

A) convergent plate boundary
B) divergent plate boundary
C) island arc along a subduction zone
D) shield

Question 21

Which of the following is a cause of warping?

A) mantle convection
B) hot spots
C) isostatic adjustment
D) all of these

Question 22

Folded layers of rock can form a wavelike pattern of troughs and crests. The layers near the trough form

A) a syncline.
B) a tension zone.
C) an anticline.
D) a thrust fault.

Question 23

High mountains consisting of tightly folded and overthrust sedimentary rock layers, as well as metamorphic rocks, are formed

A) along midocean ridges during seafloor spreading activity and are subsequently uplifted above sea level in response to isostatic processes.
B) during plate collisions.
C) during volcanic eruptions.
D) in continental rift zones.
E) exclusively by magma intrusions.

Question 24

Which of the following is $\underline {\text { not } }$ produced by normal faulting?

A) the Himalayas
B) the Basin and Range
C) the East Africa rift zone
D) the Death Valley graben

Question 25

Tensional stress along a fault can result in a dropped hanging-wall block relative to the footwall side, producing a

A) reverse fault.
B) thrust fault.
C) normal fault.
D) strike-slip fault.

Question 26

A brittle rock is likely to respond to stress by ________, whereas a ductile rock is likely to respond by ________.

A) stretching; breaking
B) breaking; bending
C) isostatically uplifting; bending
D) isostatically uplifting; breaking

Question 27

The San Andreas system in California is an example of a

A) strike-slip fault.
B) transform fault.
C) right-lateral motion.
D) All of these are correct.

Question 28

Orogenesis refers to

A) the beginning of extensive faulting.
B) a general term for the beginning of a mountain-building episode that thickens continental crust.
C) a general thinning of the crust.
D) the formation of mountains $\underline { \text { without } }$ faulting, folding, or the capture of migrating terranes.

Question 29

The Basin and Range Province in the western U.S. is a result of ________ faulting produced by ________ forces.

A) reverse; tensional
B) reverse; compressional
C) normal; tensional
D) normal; compressional

Question 30

Fault types are defined by

A) the relative motion of the hanging wall and footwall.
B) the amount of movement along the hanging wall and footwall.
C) the amount of energy liberated during movement.
D) all of these

Question 31

The greatest amount of crustal shortening would be associated with

A) a synclinal ridge.
B) a thrust fault.
C) an overturned anticline.
D) a rift zone.

Question 32

The presence of horsts and grabens indicates the occurrence of

A) volcanic activity.
B) rift activity.
C) collision activity.
D) strike-slip activity.

Question 33

Which of the following represents a surface feature whose relief is opposite that expected based on the fold pattern in the rocks of which it is composed?

A) synclinal valley
B) synclinal ridge
C) inverted anticline
D) synclinal basin

Question 34

When rock strata are strained beyond their ability to remain an intact unit, displacement occurs in a process known as

A) folding.
B) faulting.
C) broad warping.
D) stressing.

Question 35

Normal faults are associated with

A) tensional forces.
B) compressional forces.
C) plate convergence.
D) transcurrent forces.

Question 36

Which of the following can lead to the formation of mountains?

A) plate collisions and volcanic activity
B) exposure of plutons by erosion of surrounding landscape
C) faulting
D) all of the above
E) plate collisions, volcanic activity, and faulting only

Question 37

Warping produces bends in rocks that are ________ those produced by folding.

A) larger than
B) smaller than
C) the same size as

Question 38

People often say that California is going to "fall into the ocean,". This idea is totally wrong because the San Andreas fault would have to be a ________ fault associated with ________ forces for this to happen.

A) normal; tension
B) normal; compression
C) reverse; tension
D) reverse; compression
E) strike-slip; compression

Question 39

Folded layers of rock can form a wavelike pattern of troughs and crests. The layers near the crest form

A) a syncline.
B) a tension zone.
C) an anticline.
D) a thrust fault.

Question 40

Compressional stress along a fault can result in a dropped footwall block relative to the hanging-wall side, producing a

A) reverse fault.
B) lateral fault.
C) normal fault.
D) strike-slip fault.

Question 41

On average, how often would you expect an earthquake of greater than Richter 8.0 and Mercalli XII to occur?

A) 120 times a year
B) 800 times a year
C) only once every few years
D) once or twice a century

Question 42

Foreshocks may be caused by

A) the breaking of some asperities before the main movement occurs.
B) small movements that occur when some rocks break in limited areas of a fault plane prior to the main movement.
C) a limited number of lapilli breaking prior to the main movement.
D) the breaking of asperities and small movements prior to the main movement only.
E) all of these

Question 43

The motion of seismic waves is initiated in a subsurface location along the fault plane called the

A) epicenter.
B) fault area.
C) Richter zone.
D) focus.

Question 44

The wave amplitude associated with a magnitude 8 quake on the Richter scale is how many times greater than that of a magnitude 6 quake?

A) 3
B) 30
C) 100
D) 1,000
E) 1,000,000

Question 45

Which of the following is true regarding the moment magnitude scale-a scale which quantifies the amount of energy released by an earthquake?

A) It is a scale of magnitude based on arithmetical progressions (1,2,3,4, etc.).
B) It is a closed scale that begins at 0.0 and ends at 10.0.
C) An 8.0 on the scale is equal to 31.5 times more energy release than a 7.0.
D) It is the same as the Mercalli scale.

Question 46

A scale used to classify and describe the effects of earthquakes on terrain, construction, and local damage conditions is the

A) Richter scale.
B) seismograph scale.
C) seismic assessment scale.
D) modified Mercalli scale.

Question 47

The major impact of earthquake $\underline {\text { prediction } }$ on a region would be

A) a decline in business activity and damage to the local economy.
B) increased business activity.
C) an increase in property values.
D) upward changes in employment opportunities.

Question 48

Because of the processes responsible for the formation of the Himalayan Mountains, the crust in this region of the world has been

A) shortened.
B) extended.
C) folded.
D) extended and folded.
E) shortened and folded.

Question 49

Which of the following is not used to rate an earthquake on the moment magnitude scale?

A) the amount of fault slippage that occurred
B) the size of the subsurface or surface area that ruptured
C) the amount of death and destruction that occurred
D) the nature of the ground materials affected by the quake

Question 50

The area at the surface directly above the subsurface location where seismic waves are initiated is termed the

A) epicenter.
B) fault area.
C) Richter zone.
D) focus.

Question 51

On average, how often would you expect an earthquake of between moment magnitude 5.0-5.9 and Mercalli V-VII to occur?

A) 120 times a year
B) 800 times a year
C) only once every few years
D) once or twice a century

Question 52

The greatest loss of human life (250,000) this century resulted from which earthquake event?

A) northern Peru, 1970
B) Mexico City, 1985
C) Tangshan, China, 1976
D) Armenia (formerly USSR), 1988

Question 53

Small areas of high strain along a fault are termed

A) asperities.
B) focal points.
C) elastic spots.
D) sticking points.

Question 54

An instrument used to record vibrations in the crust is the

A) land barometer.
B) seismograph.
C) the Richter scale.
D) tiltmeter.

Question 55

The phrase "considerable-to-serious damage to buildings" would be used in the ________ scale.

A) Richter
B) Mercalli
C) Beaufort
D) Moh's

Question 56

Which of the following is false regarding the series of earthquakes in southern California in 1992?

A) A series of three strong earthquakes followed months of foreshocks and activity.
B) Earthquakes struck that ranged in magnitude from 6.1 to 7.4 on the Richter scale.
C) Earthquakes followed at epicenters across the western U.S.
D) The sequence did not involve the San Andreas fault system.

Question 57

The most active tectonic regions of North and South America are on the

A) western coasts.
B) eastern coasts.
C) southern coasts.
D) mid-continent.

Question 58

Seismic gaps investigations involve

A) the study of surface cracks following an earthquake.
B) paleoseismology and the history of activity along specific plate boundaries.
C) perceptual studies by sociologists.
D) the study of places where volcanoes have occurred.

Question 59

The Appalachians formed as a result of the

A) Laramide orogeny.
B) Alleghany orogeny.
C) Cordilleran orogeny.
D) Alpine orogeny.

Question 60

The Grand Tetons best represent a

A) horst.
B) graben.
C) tilted fault block.
D) anticline.

Question 61

Composite cones have steep slopes and experience ________ eruptions because they are composed of ________ magma.

A) mild; mafic
B) mild; felsic
C) violent; mafic
D) violent; felsic

Question 62

Concerning Mount Saint Helens, which of the following is not correct?

A) The Cascades lie over an area of subduction of the Juan de Fuca plate.
B) It is the youngest and smallest of the Cascade Range.
C) It is an example of a shield volcano in form.
D) The 18 May eruption resulted in less than 100 deaths.

Question 63

A cinder cone is formed from relatively ________ viscosity magma with a ________ gas content.

A) high; high
B) high; low
C) low; high
D) low; low

Question 64

Which of the following is true regarding harmonic tremors?

A) They are associated with the sharp release of energy when two pieces of land move against each other, as along a fault.
B) They are produced by sub-surface movement of magma beneath a volcano.
C) They are associated with movements in the crust caused by cities and traffic.
D) They are produced by explosive volcanic eruptions.

Question 65

Effusive eruptions are $\underline {\text { not } }$ related to which of the following?

A) magma with a 50 percent or lower silica content, rich in iron and magnesium
B) low-viscosity magma
C) magma with a 50-75 percent silica content, high in aluminum
D) the volcanic activity in Hawaii

Question 66

Pulverized rock and clastic materials ejected violently during an eruption are called

A) cinders.
B) explosive debris.
C) tephra, or pyroclastics.
D) volcanic ash.

Question 67

Many of the islands of Indonesia (Java, Sumatra, Borneo), which are located adjacent to a subduction zone next to the edge of the continental shelf of SE Asia, consist of felsic lava. This means that the lava that produces these islands is derived from

A) a midocean ridge.
B) a volcanic hot spot under the ocean floor.
C) the melting of continental shelf material along with ocean floor material.
D) the melting of subducted plate material and nothing else.
E) a rift zone.

Question 68

The North Anatolian fault in Turkey and the San Andreas fault in California are ________.

A) left-lateral, strike-slip faults
B) right-lateral, strike-slip faults
C) right-lateral, transform faults
D) faults with completely different motions
E) right-lateral, strike-slip, transform faults

Question 69

Which of the following statements about shield volcanoes is true?

A) They occur in continental shield areas.
B) They are subject to violently explosive eruptions.
C) They form from mafic magma.
D) They consist of tremendous quantities of pyroclastics.

Question 70

Explosive eruptions tend to build up

A) shield-shaped volcanoes.
B) plateau basalts.
C) composite volcanoes.
D) many subsequent lava flows.

Question 71

Which of the following is false relative to the principal locations of volcanic activity?

A) They occur along sea-floor spreading centers.
B) They occur around the perimeter of the Atlantic Ocean basin.
C) They occur in association with hot spots over plumes in the mantle.
D) They occur in the circum-Pacific belt.

Question 72

The eventual catastrophic eruption of Mount Saint Helens was

A) a total surprise.
B) within only a few days of the first earthquake.
C) not preceded by any physical activity.
D) related to seafloor subduction at the west coast of North America.

Question 73

Lava plateaus, such as the Columbia River Plateau, are formed from ________ magma, which has a ________ viscosity.

A) granitic; high
B) granitic; low
C) basaltic; high
D) basaltic; low

Question 74

Volcanic activity located $\underline { \text { away from } }$ plate boundaries is associated with

A) subduction and melting of plates along collision zones.
B) hot spots.
C) rift zones.
D) all of the above

Question 75

The topography of Earth's surface has had relatively little influence on human activities and culture.

Question 76

Geologically speaking, the continents began forming relatively recently.

Question 77

The Alps and alpine complex in Europe are an example of a third order of relief.

Question 78

Molten rock that pours forth on Earth's surface is called

A) metamorphic.
B) magma.
C) intrusive.
D) lava.

Question 79

Which of the following is $\underline {\text { not } }$ the result of $\underline {\text { extrusive } }$ volcanic activity?

A) batholith
B) lava flow
C) tephra
D) volcanic cone

Question 80

Volcanoes formed from silica-rich magma

A) have gently sloping surfaces that give them the appearance of a shield.
B) are highly explosive and dangerous.
C) are associated with midocean ridges.
D) are associated with rift zones.