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8th Science - Earth and Space > Test 2, Chapter 2 > Flashcards

Test 2, Chapter 2 Flashcards

1
Q

The most abundant element in the earth’s crust is ____

A

oxygen

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2
Q

In what type of fault do rocks along one side of the fault move horizontally along the fault?

A

strike-slip fault

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3
Q

Eighty-five percent of all earthquacks are _____ earthquakes

A

shallow-focus

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4
Q

A bowl-shaped hollow more than 2 miles wide, formed by the collapse of an underground magma chamber, is a

A

caldera

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5
Q

The point deep in the earth at which an earthquake begins is the

A

focus

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6
Q

What are large almond-or teardrop-shaped pieces of ejecta formed when lava solidifies

A

volcanic bomb

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7
Q

The narrow zone of active volcanoes that nearly encircles the Pacific basin is the

A

Ring of Fire

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8
Q

About 80% of the world’s earthquakes occur in

A

the circum-Pacific belt

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9
Q

The bending or buckling of rocks under great force produces a(n)

A

fold

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10
Q

The inner core of the earth is thought to be

A

solid

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11
Q

An inactive volcano that can erupt again is

A

dormant

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12
Q

The middle of the earth’s three layers is the

A

mantle

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13
Q

An instrument used to record the vibrations caused by earthquakes is a(n)

A

seismograph

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14
Q

A large, well known strike-slip fault in western California is the

A

San Andreas Fault

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15
Q

The study of the earth is

A

geology

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16
Q

The study of earthquakes is

A

seismology

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17
Q

All the present-day continents are thought to have been one land mass called

A

Pangaea

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18
Q

An earthquake caused by sudden movements of rock beneath the earth’s surface is a(n)

A

tectonic earthquake

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19
Q

A domelike igneous intrusion formed when magma bulges overlying rocks upward is a(n)

A

laccolith

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20
Q

type of volcano consisting primarily of erupted volcanic ash and rock fragments held loosely together

A

cinder-cone volcano

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21
Q

broad, gently sloping volcano made of large quantities of highly fluid lava that hardened into rock

A

shield volcano

22
Q

volcano formed partly by explosive eruptions of ash and rock fragments and partly by mild lava flows

A

composite volcano

23
Q

The ______ theory states that rocks spring back to a position of little or no strain at the moment of an earthquake, causing vibrations in the earth’s crust

A

elastic rebound

24
Q

The fastest type of earthquake waves are _____

A

P waves

25
Q

Small earthquakes that often follow a larger earthquake at frequent intervals for days or even months are called _____

A

aftershocks

26
Q

The most famous scale of earthquake strength, which rates earthquakes on a scale of 1-9, is the _______

A

Mercalli scale

27
Q

Deposits of sand and mineral fragments, usually laid down by water, are known as _____

A

sediments

28
Q

The underground ______ is the actual source of a volcanic eruption

A

magma chamber

29
Q

A ___ is a sheetlike igneous intrusion formed when magma hardens in a vertical crack

A

dike

30
Q

type of mountain formed when molten rock collects beneath an overlying rock layer, forcing the layer upward into a blisterlike structure

A

domed mountain

31
Q

type of mountain formed when rocks on one side of a fault are forced upward and the rocks on the other side are forced downward

A

fault-block mountain

32
Q

type of mountain formed when molten rock erupts from a hole in the earth’s crust

A

volcanic mountain

33
Q

type of mountain formed when two rock layers are pushed together, causing the layers to buckle

A

folded mountain

34
Q

The point on the earth’s surface directly above the point where an earthquake begins is the

A

epicenter

35
Q

What is an archlike structure formed when rocks are folded upward?

A

anticline

36
Q

The channel in a volcano through which gases, ash, and molten rock are ejected from the earth’s interior is the

A

vent

37
Q

A superheated, incandescent cloud of gas and volcanic ash that flows swiftly down a volcanic slope is called

A

pyroclastic flow

38
Q

Lava that hardens into rough, jagged rocks with a crumbly or ‘‘blocky’’ texture is __ lava

A

aa

39
Q

What is a troughlike structure formed when rocks are folded downward

A

syncline

40
Q

Lava that hardens into a smooth-textured rock with a ‘‘ropy’’ appearance is ___ lava

A

pahoehoe

41
Q

A particle or block of solid volcanic ejecta is a(n)

A

pyroclast

42
Q

In what type of fault are rocks on one side of a fault shoved on top of the rocks on the other side

A

thrust fault

43
Q

A volcano that has erupted within recorded history or is currently producing seismic activity is

A

active

44
Q

The central portion of the earth is the

A

core

45
Q

Where are the effects of an earthquake most severe

A

epicenter

46
Q

In what kind of fault do rocks along one side of the fault sink vertically

A

normal fault

47
Q

What is the boundary line between the crust and the mantle called

A

Mohorovicic discontinuity (Moho)

48
Q

What is molten rock beneath the surface of the earth called

A

magma

49
Q

What theory states that the earth’s crust and upper mantle consist of huge plates slowly drifting because of convection currents in the mantle?

A

plate tectonics

50
Q

What is the area between the upper mantle and the lower mantle called

A

transition zone

51
Q

What is an underground channel that formed when surface lava hardened before the lava underneath it

A

lava tunnel

52
Q

Compare and contrast fixed-base systems, base-isolated systems, and energy-dissipation devices.

A

Answers should include the following ideas:

A fixed-base system is a type of foundation in which the building is attached to bedrock; the energy of an earthquake is absorbed by the building’s frame and joints. A downside to this system is that the building may be deformed.

Base-isolated systems are the most common new construction for earthquake resistance. In a base-isolated system, the building is on stiltlike isolators, which separate the building from the foundation and absorb seismic energy.

Energy-dissipation devices are added to structures to absorb seismic energy, lessening the stress on the building and thereby minimizing deformation.

8th Science - Earth and Space (48 decks)

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