Chapter 8-Dynamic Earth Flashcards Preview

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Flashcards in Chapter 8-Dynamic Earth Deck (66):
1

Continental drift

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

2

Pangaea

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.

3

Panthalassa

the vast sea surrounding the supercontinent of Pangaea

4

Plate tectonics

the theory concerning the movement of the continental plates

5

Mantle

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

6

Convection Current

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

7

Continental Crust

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

8

Oceanic Crust

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.

9

Subduction

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

10

Destructive Plate Boundry

a convergent boundary where two plates collide

11

Constructive plate

plate that creates new land from cooling magma

12

Seismic Waves

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

13

Ocean Ridges

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

14

Laurasia

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

15

Gondwanaland

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

16

Hotspots

a localised place where an activity occurs

17

Folding

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

18

Anticlines

Folds that bend upwards

19

Synclines

folds that bend downwards

20

Fault

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

21

Rift valleys

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

22

Horst

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

23

Slip fault

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

24

Tremors

vibration on the Earth’s surface caused by an earthquake

25

Epicentre

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

26

Focus

the point at which an earthquake begins

27

Triangulation

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

28

Seismograph

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

29

Richter Scale

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

30

P-Waves/ Primary Waves

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

31

Secondary waves/ S-waves

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.

32

Body Waves

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

33

Seismologists

a scientist who studies earthquakes

34

Tsunami

a powerful ocean wave triggered by an undersea earth movement

35

Ocean Ridges

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

36

Laurasia

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

37

Gondwanaland

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

38

Hotspots

a localised place where an activity occurs

39

Folding

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

40

Anticlines

Folds that bend upwards

41

Synclines

folds that bend downwards

42

Fault

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

43

Rift valleys

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

44

Horst

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

45

Slip fault

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

46

Tremors

vibration on the Earth’s surface caused by an earthquake

47

Epicentre

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

48

Focus

the point at which an earthquake begins

49

Triangulation

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

50

Seismograph

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

51

Richter Scale

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

52

P-Waves/ Primary Waves

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

53

Secondary waves/ S-waves

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.

54

Body Waves

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

55

Seismologists

a scientist who studies earthquakes

56

Tsunami

a powerful ocean wave triggered by an undersea earth movement

57

Volcanoe

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

58

Magma

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

59

Volcanic/Lava Bomb

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

60

Magma

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

61

Magma

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

62

Lava

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

63

Lava

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

64

Active

describes a volcano that is erupting or has recently erupted

65

Extinct

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

66

Dormant

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