Restless Earth Flashcards

1
Q

What is the earth’s surface separated into?

A

Tectonic plates

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2
Q

What two types of crust are there?

A

Oceanic and continental

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3
Q

What is the centre of the earth called and made of?

A

Core - solid iron and nickel

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4
Q

What is the mantle?

A

The layer on top of the core made of semi-molten rock that moves very slowly

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5
Q

What is the outer layer of the earth? How thick is it?

A

The crust, from 0 to 40km thick

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6
Q

Describe the characteristics of continental crust…

A

It’s thick and less dense than oceanic.

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7
Q

Describe the characteristics of oceanic crust…

A

It’s thinner than continental but denser as it’s compressed sediment.

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8
Q

Why do plates move?

A

Due to the moving mantle underneath them

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9
Q

What do you call the area where plates meet?

A

Plate margins/ boundaries

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10
Q

What are the three types of plate boundary?

A

Destructive,
Constructive,
Conservative

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11
Q

Which way do destructive plates move? e.g

A

Towards each other, along the coast of Japan.

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12
Q

Destructive - what happens when an oceanic plate meets a continental? WHY?

A

The oceanic is subducted because it’s denser, into the mantle and melted. This often forms volcanoes as the rock melts, and deep ocean trenches.

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13
Q

What happens to the crust when two continentals collide?

A

No crust is destroyed

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14
Q

In what direction are plates moving when constructive? e.g

A

Away from each other, mid-Atlantic ridge

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15
Q

What happens when plates diverge and converge?

A

Diverge, they move away from each other

Converge, the move closer

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16
Q

What happens when plates diverge?

A

Magma rises from the mantle to fill the gap and cools, creating new crust.

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17
Q

What is conservative movement? Where?

A

When two plates move sideways past each other either in the same or different direction at different speeds. Nothing is created or destroyed. The west coast of the USA.

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18
Q

Explain convection currents, with plates?

A

Caused by radioactive decay in the earth’s core creating convection currents in the mantle. The mantle moves with these and pulls the plate in their direction, this is why they move.

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19
Q

At what margin are fold mountains formed?

A

Destructive margins

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20
Q

What has to be between the continental and continental/destructive plates to form fold mountains at destructive plate boundaries?

A

Sedimentary rock.

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21
Q

What geographical formation is squished to form fold mountains?
What happens to sedimentary rock when compressed between two plates converging?

A

A geosyncline filled with sediment and water.

They fold upwards together to form fold mountains.

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22
Q

Where are fold mountains found?

A

Where there are/ used to be destructive plate boundaries. West coast of North America.

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23
Q

Give an example of when continental and oceanic plates collide to form fold mountains…

A

Andes in South America

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24
Q

Give an example of when continental and continental plates collide to form fold mountains…

A

Himalayas in Asia.

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25
Q

Why are fold mountains used for… farming? and how?

A

Higher mountain slopes aren’t good for growing crops, but are good for grazing animals, e.g goats.
Lower slopes are also used for crop growing and the highers can be terraced for this.

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26
Q

Why are fold mountains used for… hydro-electric power?

A

Step sided mountains and high lakes for water storage are ideal for this.

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27
Q

Why are fold mountains used for… mining?

A

They’re a major source of metal ores. Steep mountains are hard to access so zigzag paths have been cut for easy access.

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28
Q

Why are fold mountains used for… forestry?

A

Good for growing trees like conifers to be cut for fuel, building materials and for paper and furniture.

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29
Q

Why are fold mountains used for… tourism?

A

Spectacular scenery - tourists
Winter - skiing, snowboarding, ice climbing
Summer - walkers for the scenery
Tunnels drilled through the mountains for fast straight roads, improves communication for tourists and locals.

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30
Q

At which boundaries are volcanoes found?

A

Constructive and destructive boundaries

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31
Q
How are volcanoes formed at destructive margins?
Plates.
Forms?
Crust
Erupt
A

The oceanic plate is subducted into the mantle and melted and destroyed, this forms a pool of magma.
This rises through cracks in the crust called vents.
The magma erupts onto the surface, then called lava, forming a volcano.

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32
Q

How are volcanoes formed at constructive margins?
Plates.
Forms?

A

As the plates move apart magma rises between them.

The magma coming up forms the volcano.

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33
Q

What is the third unusual formation of a volcano?

A

At hot spots, over very hot bits of mantle. e.g Hawii

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34
Q

Describe a composite volcano…

  1. Composition
  2. Lava
  3. Shape
A

It’s made up of ash and lava that’s erupted and cooled in layers.
The lava is thick and flows slowly hardening quickly to form a steep sided volcano.

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35
Q
Describe a shield volcano...
1. Composition
2. Lava 
3. Shape
(Dome is a shield with thick lava.)
A

Made up of only lava.
The lava is runny.
This means it flows quickly and spreads over a wide area forming a low, flat volcano.

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36
Q

What are the two main types of volcano?

A

Composite, Shield

Dome is a shield with thick lava.

37
Q

Why should volcanic eruptions be monitored or predicted?

A

Because lots of people live around them and are at risk.

38
Q

What are the telling signs of a possible volcanic eruption?

A

Tiny earthquakes
Escaping gas
Change in the shape of the volcano or the ground where magma has built up underneath it.

39
Q

What are supper volcanoes?

Where do they form?

A

Massive volcanoes

At destructive margins and hot spots above the mantle.

40
Q

Where and why (simple) did the Yellowstone super volcano form?

A

It’s above a hot spot in a National Park in the USA.

41
Q

What are the three characteristics of a super volcano?
Shape
Spread
Level

A

Flat - unlike normal mountain volcanoes
Cover a large area - much bigger than normal
Have a caldera - normally there’s just a small crater at the top.

42
Q

Describe how super volcanoes are formed at a hot spot…

The formation of the magma basin…

A

Magma rises through cracks in the crust to form a large magma basin below the surface. The pressure of the magma forms a circular bulge in the earth several kilometers wide.

43
Q

Describe how super volcanoes are formed at a hot spot…

The first eruption…

A

The bulge eventually cracks creating vents for the magma to escape.
As the lava erupts from the vents earthquakes are caused and it sends up massive plumes of ash and rock.

44
Q

Describe how super volcanoes are formed at a hot spot…

The collapse…

A

As the magma basin has emptied the bulge at the top can no longer be supported.
It collapses and spews out more magma.

45
Q

Describe how super volcanoes are formed at a hot spot…

The caldera…

A

After the eruption a big caldera crater is left where the roof of the magma basin collapsed. These can get filled with water to form lakes, like Lake Toba in Indonesia.

46
Q

When and which super volcano was the last to erupt?

A

Lake Toba super volcano 74,000 years ago.

47
Q

List the 4 global effects of a super volcano eruption…

What will the super volcano throw out?

A
  1. The eruption will throw out thousands of cubic kilometers of rock, ash, and lava., normal volcanoes only throw a few cubic kilometers of this.
48
Q

List the 4 global effects of a super volcano eruption…

What will the products of the super volcano do to its surroundings?

A

A thick cloud of super heated gas and ash will flow at high speed from the volcano, killing and burning, and, burying everything it touches. Everything within tens of miles will be destroyed.

49
Q

List the 4 global effects of a super volcano eruption…

What are the effects on the atmosphere?

A

Ash will shoots kilometers in the air blocking out almost all of the sunlight over whole continents. This can trigger mini ice ages from the reduction in heat energy from the sun getting to the Earth.

50
Q

List the 4 global effects of a super volcano eruption…

Where will the ash settle?

A

Over hundreds of square kilometers of fields and buildings, burying them.

51
Q

Why are earthquakes caused?

A

Tension builds up at all three types of plate margin…

52
Q

How does tension build up at all the margins to lead to earthquakes?
Destructive:
Constructive:
Conservative:

A
  1. Destructive - plates get stuck when being subducted
  2. Constructive - tension builds along cracks within the plates as they move away from each other.
  3. Conservative - it builds when the grind against each other and get stuck
53
Q

How are the shock waves (earthquakes) caused?

A

When the plates eventually jerk past each other.

54
Q

What happens at the focus?

A

The shock waves spread out from the focus, the point in the earth where the earthquake starts. Near it the waves are stronger and cause more damage.

55
Q

What’s the focus?

A

The point in the earth where the earthquake originated.

56
Q

What is the epicentre?

A

The point on the earth’s surface straight above the focus.

57
Q

Describe the frequency of earthquakes depending on their size…

A

Weak earthquakes happen quite often, and strong are rare.

58
Q

Name the two ways earthquakes can be measured…

A

The Richter Scale

The Mercalli scale

59
Q

What does the Richter scale measure, using what instrument?

A

The amount of energy released from the earthquake, it’s magnitude.
Using a seisometer - a machine with an arm holding a pen that moves with the vibrations of the earth.

60
Q

What is the RC’s scale like, meaning what for 2,3?

What do people usually feel?

A

It’s logarithmic so it doesn’t meaning that an earth quake with a magnitude of 3 is ten times more powerful than 2.
Earthquakes of 3 above, 5 above are major.

61
Q

What does the Mercalli scale measure?
How are these measured?
Scale?

A

Measures the effects of the earthquake.
Asking eye witnesses for observations of what happened. - in words or photos.
1-12

62
Q

What is a case study for a volcanic eruption?

What year?

A

Soufriere Hills Volcanic eruption, Montserrat, Caribbean, 1997

63
Q

What was the cause of the Soufriere Hills Volcanic eruption?

A

The north American plate is being subducted by the denser continental Caribbean plate creating the Puerto Rico trench.
The gases and water trapped in the sediment heats up when subducted and rises building up pressure along with rising magma, it then explodes.
This happens over and over again forming a rocky composite volcano.

64
Q

Where is Montserrat and the Soufriere Hills Volcano?

A

Montserrat is an island in the Caribbean near the Puerto Rico trench

65
Q

What were the primary effects of the Soufriere Hills Volcanic eruption? (4)

A

Lahars and pyroclastic flows
40ft of mud and ash covered capital Plymouth
Homes, animals, crops destroyed in the eruption
19 people were killed by the pyroclastic flow.

66
Q

What were the secondary effects of the Soufriere Hills Volcanic eruption? (4)

A

Industry in rice, fish has declined due to the destruction
The tourist industry initially stopped as the airport closed
Breathing difficulties due to the ash
Shortage of available building land

67
Q

What were the immediate responses for the Soufriere Hills Volcanic eruption? (2)

A

An exclusion zone created to keep people out of danger

Population on the island reduced to 5000 as 8000 were evacuated.

68
Q

What were the long term responses for the Soufriere Hills Volcanic eruption? (3)
Long term effects: (2)

A

The British government is helping people to rebuild by giving 41 million.
5000 people were moved to the north of the island away from the volcano
A charity concert took place in the Royal Albert Hall to raise money

Tourism has increased as people want to see the volcano
Living conditions are poor in the north as there aren’t enough schools or hospitals.

69
Q

What six ways are there to monitor or predict volcanic eruptions?

A
Tiltmeters
GPS
Spiders
Digital Cameras
Seisometers
Historic records
70
Q

How are tiltmeters used to monitor or predict volcanic eruptions?

A

They can detect a slight change in the volcano shape cause by the moving of magma beneath it.

71
Q

How is GPS used to monitor or predict volcanic eruptions?

A

It uses satellites to detect earth movement by as little as 1mm

72
Q

How are spiders used to monitor or predict volcanic eruptions?

A

Robots can be sent close to the volcano to measure changes in gas emissions

73
Q

How are Digital Cameras used to monitor or predict volcanic eruptions?

A

Can be placed on the rim of the crater to photograph any changes or events safely

74
Q

How are seisometers used to monitor or predict volcanic eruptions?

A

The sensor measures very small earth quakes caused by the magma rising inside the volcano.

75
Q

How are historic records used to monitor or predict volcanic eruptions?

A

Looking at past eruptions can help scientists to estimate when and how the volcano might erupt again.

76
Q

What are the case studies for earthquakes in an MEDC and LEDC? (dates)

A

Haiti 2010

Kobe 1995

77
Q

What was the cause of the Haiti earthquake?

What was the cause of the Kobe earthquake?

A

In the Caribbean sea, east of Cuba it sits on a conservative plate boundary, the Caribbean plate and the NAmerican plate. The earthquake happened near the capital Port-au-Price
Stress built up in the rocks between the Pacific and Philippeans plate, the stress was released, where the epicentre was very close to Kobe.

78
Q

What were the primary effects from the Haiti earthquake? (3) Dead, homeless, buildings
What were the primary effects from the Kobe earthquake? (3)
Dead
Homeless
Extra

A

230,000 people died
1 million made homeless
300,000 buildings collapsed or were severely damaged and many hospitals were destroyed making difficult to treat the injured

5000 people died,
350,000 made homeless
Gas pipes exploded causing fires to burn all over the city
Smoke and collapsed buildings made it hard to search for survivors

79
Q

What were the secondary effects from the Haiti earthquake? (3)
What were the secondary effects from the Kobe earthquake? (-)

A

The tourist industry has been severely affected
Haiti’s economy has suffered, 1 in 5 jobs lost
Little clean water, high risk of disease
Kobe - few as the country is more developed and could cope with the destruction, they aren’t too dependent on their tourist industry

80
Q

What were the short term responses from the Haiti earthquake? (2)
What were the short term responses from the Kobe earthquake? (2)

A

The Pitts donated $1,000,000 to help Haiti
Many countries sent large amounts of aid and medical staff
Kobe - Survivors immediately taken to a central building with food water and blankets
Fire engines sent out to stop the fires but ran out of water

81
Q

What were the long term responses from the Haiti earthquake? (2)
What were the long term responses from the Kobe earthquake? (2)

A

Aid agencies will help Haitians to rebuild their houses, Oxfam will help to build earthquake proof houses
The government needs to stabilise and work effectively so that the problems can be avoided
Kobe -Buildings in central Kobe are being rebuilt with computer controlled foundations to adjust to earth movements
Rebuilt houses are being made earthquake proof

82
Q

What were the causes of the 2004 Boxing Day tsunami in South-east Asia?
Plates
Caused a what?
This was how long and turned into what?

A

The Indian plate was subducted by the Eurasian plate in the Indian ocean, where the epicentre was, energy built up from the subduction friction and eventually the plate springs up and the energy is released.
The crust rose 30ft causing a wide shallow wave to sweep across the ocean.
The front of the 100 mile wave slows down due to friction and the back catches up and causes the wave to become giant and tall and crashing.

83
Q
What were the primary effects of the 2004 Boxing Day tsunami in South-east Asia? (4)
Wave
Dead
Homeless
Water
A

The wave crashed over the land, rushing through cities dragging debris and collapsing buildings.
230,000 people dead in Thailand
1.7 million homeless
Contaminated water

84
Q

What were the secondary effects of the 2004 Boxing Day tsunami in South-east Asia? (3)

A

Thousands killed by disease from contaminated water
Water mixed with sewage - malaria, diarrhoea etc
Disease will spread

85
Q

What were the short term responses of the 2004 Boxing Day tsunami in South-east Asia? (2)

A

Britain sent out aid, food, shelter, water
The dead buried quickly to stop the spread of disease
People rescued from the sea/buildings and vehicles

86
Q

What were the long term responses of the 2004 Boxing Day tsunami in South-east Asia? (3)

A

Increase hazard defenses of affected areas
Improvement to emergency plans and educating the public about warning signs and what to do
Rebuilding homes, cities, and businesses, e.g fishing

87
Q

How do countries predict earthquakes? (2)

A

Seisometers measure vibrations in the crust which could mean an earthquake is likely
Radon gas escapes from cracks in the crust, so levels can be monitored, a sudden increase may suggest an earthquake.

88
Q

How do countries prepare and protect themselves for earthquakes? (3)

A

People living in earthquake zones have been trained with earthquake drills, people are also educated via TV or radio.
People may put together emergency kits and store them in their homes. An emergency kit may include first-aid items, blankets and tinned food.
earthquake proof buildings built to protect cities from earthquakes, e.g San Fransico