Chapter 8-Dynamic Earth

Question 1

Continental drift

Answer 1

movement of the plates of the Earth’s crust in relation to each other

Question 2

Pangaea

Answer 2

a super-continent that existed about 225 million years ago. All of the landmasses that existed at this time were joined together to form this super-continent.

Question 3

Panthalassa

Answer 3

the vast sea surrounding the supercontinent of Pangaea

Question 4

Plate tectonics

Answer 4

the theory concerning the movement of the continental plates

Question 5

Mantle

Answer 5

Thick layer inside the Earth, below the crust. Most of the mantle is solid rock, although the upper part is molten rock called magma

Question 6

Convection Current

Answer 6

circular movement that occurs when warmer, less dense fluid particles rise and cooler, denser fluid particles sink

Question 7

Continental Crust

Answer 7

the plates of the Earth’s crust that make up the land

Question 8

Oceanic Crust

Answer 8

one of the types of crust that makes up the Earth’s outer layer. Oceanic crust is thinner than continental crust and made up of dense, heavy rocks such as basalt.

Question 9

Subduction

Answer 9

process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust

Question 10

Destructive Plate Boundry

Answer 10

a convergent boundary where two plates collide

Question 11

Constructive plate

Answer 11

plate that creates new land from cooling magma

Question 12

Seismic Waves

Answer 12

Seismic waves: waves of energy that travel through the Earth’s crust, caused by earthquakes

Question 13

Ocean Ridges

Answer 13

an area where the tectonic plates move apart, allowing magma from the mantle to rise, forming underwater volcanoes and creating new oceanic crust as it is cooled and solidified by sea water

Question 14

Laurasia

Answer 14

one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

Question 15

Gondwanaland

Answer 15

One of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

Question 16

Hotspots

Answer 16

a localised place where an activity occurs

Question 17

Folding

Answer 17

buckling of rocks caused when rocks are under pressure from both sides

Question 18

Anticlines

Answer 18

Folds that bend upwards

Question 19

Synclines

Answer 19

folds that bend downwards

Question 20

Fault

Answer 20

a break in a rock structure causing a sliding movement of the rocks along the break

Question 21

Rift valleys

Answer 21

a sunken area where two blocks of crust have dropped down between faults

Question 22

Horst

Answer 22

a block of the Earth’s crust, with faults on either side, that has been pushed upwards by the forces below

Question 23

Slip fault

Answer 23

a geological feature where movement along a fault is sideways—that is, where the blocks of crust slip horizontally past each other

Question 24

Tremors

Answer 24

vibration on the Earth’s surface caused by an earthquake

Question 25

Epicentre

Answer 25

the point on the Earth’s centre directly above the site where an earthquake originates

Question 26

Focus

Answer 26

the point at which an earthquake begins

Question 27

Triangulation

Answer 27

finding a location by using at least three different sources of detection

Question 28

Seismograph

Answer 28

an instrument used to detect and measure the intensity of an earthquake

Question 29

Richter Scale

Answer 29

a scale that measures the amount of energy released during an earthquake

Question 30

P-Waves/ Primary Waves

Answer 30

compression waves that move through the Earth in the same way that sound waves move through air

Question 31

Secondary waves/ S-waves

Answer 31

the second set of waves to be detected after P-waves. During seismic activity, secondary waves or S-waves travel in the form of transverse waves.

Question 32

Body Waves

Answer 32

waves that travel through the interior of the Earth; P-waves and S-waves are said to be body waves

Question 33

Seismologists

Answer 33

a scientist who studies earthquakes

Question 34

Tsunami

Answer 34

a powerful ocean wave triggered by an undersea earth movement

Question 35

Ocean Ridges

Answer 35

an area where the tectonic plates move apart, allowing magma from the mantle to rise, forming underwater volcanoes and creating new oceanic crust as it is cooled and solidified by sea water

Question 36

Laurasia

Answer 36

one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

Question 37

Gondwanaland

Answer 37

One of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

Question 38

Hotspots

Answer 38

a localised place where an activity occurs

Question 39

Folding

Answer 39

buckling of rocks caused when rocks are under pressure from both sides

Question 40

Anticlines

Answer 40

Folds that bend upwards

Question 41

Synclines

Answer 41

folds that bend downwards

Question 42

Fault

Answer 42

a break in a rock structure causing a sliding movement of the rocks along the break

Question 43

Rift valleys

Answer 43

a sunken area where two blocks of crust have dropped down between faults

Question 44

Horst

Answer 44

a block of the Earth’s crust, with faults on either side, that has been pushed upwards by the forces below

Question 45

Slip fault

Answer 45

a geological feature where movement along a fault is sideways—that is, where the blocks of crust slip horizontally past each other

Question 46

Tremors

Answer 46

vibration on the Earth’s surface caused by an earthquake

Question 47

Epicentre

Answer 47

the point on the Earth’s centre directly above the site where an earthquake originates

Question 48

Focus

Answer 48

the point at which an earthquake begins

Question 49

Triangulation

Answer 49

finding a location by using at least three different sources of detection

Question 50

Seismograph

Answer 50

an instrument used to detect and measure the intensity of an earthquake

Question 51

Richter Scale

Answer 51

a scale that measures the amount of energy released during an earthquake

Question 52

P-Waves/ Primary Waves

Answer 52

compression waves that move through the Earth in the same way that sound waves move through air

Question 53

Secondary waves/ S-waves

Answer 53

the second set of waves to be detected after P-waves. During seismic activity, secondary waves or S-waves travel in the form of transverse waves.

Question 54

Body Waves

Answer 54

waves that travel through the interior of the Earth; P-waves and S-waves are said to be body waves

Question 55

Seismologists

Answer 55

a scientist who studies earthquakes

Question 56

Tsunami

Answer 56

a powerful ocean wave triggered by an undersea earth movement

Question 57

Volcanoe

Answer 57

natural opening in the Earth’s crust connected to areas of molten rock deep inside the crust

Question 58

Magma

Answer 58

a very hot mixture of molten rock and gases, just below the Earth’s surface, that has come from the mantle

Question 59

Volcanic/Lava Bomb

Answer 59

large rock fragment that is blown out of erupting volcanoes; also known as a lava bomb

Question 60

Magma

Answer 60

a very hot mixture of molten rock and gases, just below the Earth’s surface, that has come from the mantle

Question 61

Magma

Answer 61

a very hot mixture of molten rock and gases, just below the Earth’s surface, that has come from the mantle

Question 62

Lava

Answer 62

mixture of molten rock and gases that has reached the Earth’s surface from a volcano

Question 63

Lava

Answer 63

mixture of molten rock and gases that has reached the Earth’s surface from a volcano

Question 64

Active

Answer 64

describes a volcano that is erupting or has recently erupted

Question 65

Extinct

Answer 65

describes a volcano that has not erupted for thousands of years and is effectively dead

Question 66

Dormant

Answer 66

describes a volcano that has not erupted for more than 20 years but is not considered extinct