Abeka Grade 8: Science Test 2

Front 1

The most abundant element in the earth's crust is __?__.

Back 1

oxygen

Front 2

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

Back 2

strike-slip fault

Front 3

Eighty-five percent of all earthquakes are __?__ earthquakes.

Back 3

shallow-focus

Front 4

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

Back 4

caldera

Front 5

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

Back 5

focus

Front 6

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

Back 6

volcanic bomb

Front 7

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

Back 7

Ring of Fire

Front 8

About 80% of the world's earthquakes occur in __?__.

Back 8

the circum-Pacific belt

Front 9

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

Back 9

fold

Front 10

The inner core of the earth is thought to be __?__.

Back 10

solid

Front 11

An inactive volcano that can erupt again is __?__.

Back 11

dormant

Front 12

The middle of the earth's three main layers is the __?__.

Back 12

mantle

Front 13

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

Back 13

seismograph

Front 14

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

Back 14

San Andreas Fault

Front 15

The study of the earth is __?__.

Back 15

geology

Front 16

The study of earthquakes is __?__.

Back 16

seismology

Front 17

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

Back 17

Pangaea

Front 18

An earthquake caused by sudden movements of rock beneath the earth's surface is a(n) __?__.

Back 18

tectonic earthquake

Front 19

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

Back 19

laccolith

Front 20

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

Back 20

cinder-cone volcano

Front 21

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

Back 21

shield volcano

Front 22

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

Back 22

composite volcano

Front 23

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.

Back 23

elastic rebound

Front 24

The fastest type of earthquake waves are __?__.

Back 24

P waves

Front 25

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

Back 25

aftershocks

Front 26

The most famous scale of earthquake strength, which rates earthquakes on a scale of 1 to 10, is the __?__.

Back 26

Richter scale

Front 27

Deposits of sand and mineral fragments, usually laid down by water, are known as __?__.

Back 27

sediments

Front 28

The underground __?__ is the actual source of a volcanic eruption.

Back 28

magma chamber

Front 29

A __?__ is a sheetlike igneous intrusion formed when magma hardens in a vertical crack.

Back 29

dike

Front 30

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

Back 30

domed mountain

Front 31

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

Back 31

fault-block mountain

Front 32

Type of mountain formed when molten rock erupts from a hole in the earth's crust

Back 32

volcanic mountain

Front 33

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

Back 33

folded mountain

Front 34

The points on the earth's surface directly above the point where an earthquake begins is the __?__.

Back 34

epicenter

Front 35

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

Back 35

anticline

Front 36

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

Back 36

vent

Front 37

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

Back 37

pyroclastic flow

Front 38

Lava that hardens into rough, jagged rocks with a crumbly or "blocky" texture is __?__ lava.

Back 38

aa

Front 39

What is the troughlike structure formed when rocks are folded downward?

Back 39

syncline

Front 40

Lava that hardens into a smooth-textured rock with a "ropy" appearance is __?__ lava.

Back 40

pahoehoe

Front 41

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

Back 41

pyroclast

Front 42

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

Back 42

thrust fault

Front 43

A volcano that has erupted within record history or is currently producing seismic activity is __?__.

Back 43

active

Front 44

The central portion of the earth is the __?__.

Back 44

core

Front 45

Where are the effects of an earthquake most severe?

Back 45

epicenter

Front 46

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

Back 46

normal fault

Front 47

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

Back 47

Mohorovicic discontinuity (Moho)

Front 48

What is the molten rock beneath the surface of the earth called?

Back 48

magma

Front 49

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

Back 49

plate tectonics

Front 50

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

Back 50

transition zone

Front 51

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

Back 51

lava tunnel

Front 52

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

Back 52

A foundation where the building is attached to bedrock is called a fixed-base system. The energy from an earthquake is absorbed by the building's frame and joints. This system could cause the building to be deformed.

The most common new construction for earthquake resistance buildings are called based-isolated systems. Buildings on stiltlike isolators, that separate the building from the foundation and absorb seismic energy are called base-isolated systems. Energy-dissipation devices are added to structures to absorb seismic energy, decreasing the stress on the building and helps to minimize deformations.