Year 9 - Topic 1 - Tectonics Flashcards

1
Q

What four layers is the Earth divided into?

A

Crust
Mantle
Outer Core
Inner Core

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2
Q

What do tectonic plates do?

A

Tectonic plates are ‘floating’ on the semi-molten layer of rock in the mantle

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3
Q

What is the crust of the Earth divided into?

A

Tectonic plates

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4
Q

What are the two types of crust?

A

Continental crust

Oceanic crust

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5
Q

What is continental crust?

A

Forms the land, is low density (light) and is 30-50km thick

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6
Q

What is oceanic crust?

A

Forms under the sea, dense (heavy) and is 6-8km thick.

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7
Q

Explain convection currents

A

Heat from the core causes convection currents in the mantle where the heated rock rises towards the crust.
This causes the tectonic plates (crust) to move constantly - either towards or away from one another.

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8
Q

What is a plate boundary?

A

A plate boundary is the point at which two tectonic plates meet

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9
Q

What are the three plate boundaries?

A

Constructive plate boundary
Destructive plate boundary
Conservative plate boundary

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10
Q

What is a constructive plate boundary?

A

Two tectonic plates are moving apart from one another. The gap in the crust causes magma to rise and cool. Earthquakes and volcanoes occur here.

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11
Q

What is a destructive plate boundary?

A

When two plates move towards each other one sinks (subducts) below the other one. Volcanoes and earthquakes occur here.

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12
Q

What is a conservative plate boundary?

A

When two plates are moving side by side, in different directions or the same direction but at different speeds. Earthquakes occur here.

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13
Q

What is an earthquake?

A

An earthquake is the shaking and vibration of the Earth’s crust. It happens when the Earth’s tectonic plates move. They can happen along any of the plate boundaries.

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14
Q

What is a volcano?

A

A volcano is an opening in the Earth’s surface through which lava and ash escape. Volcanoes can be found at destructive or constructive plate boundaries.

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15
Q

What are the two types of volcanoes?

A

Shield Volcano

Composite Volcano

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16
Q

Describe shield volcanoes

A

Wide base
Gently sloping sides
Runny lava
Eruptions are frequent and produce ash

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17
Q

Describe composite volcanoes

A

Cone shaped
Steep sided
Sticky lava
Eruptions are violent but not frequent

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18
Q

What is a tsunami?

A

A tsunami is a large wave caused by the displacement of a large amount of water when an earthquake occurs under the sea. This creates a wave that increases in height as it approaches the shore.

19
Q

What are social effects of tsunamis?

A

High death rate
People become homeless because homes and buildings are destroyed
Threat of disease

20
Q

What are economic effects of tsunamis?

A

Ports are ruined
Businesses are destroyed (e.g. the destruction of ships can affect fishing businesses)
Loss of earnings from tourism

21
Q

What are environmental effects of tsunamis?

A

Crops are destroyed
Farmland ruined by saltwater
Large oil spills can occur

22
Q

What were short-term responses from the Indian Ocean Tsunami (2009)?

A

Quick burial or burning of the dead to prevent spread of disease
$7 billion of foreign aid

23
Q

What were the long-term responses from the Indian Ocean Tsunami (2009)?

A

Indian Ocean Tsunami warning system set up

Charities set up small scale projects to help local people rebuild lives

24
Q

What are general effects of volcanoes?

A

Lava can kill and destroy farmland
Heavy pyroclastic flow can cause buildings to collapse
Gas, dust, ash and cinder bombs can fly out of the volcano causing injury and death
Dust from volcano can cause planes to crash
Toxic gases can cause health problems e.g. breathing problems and eye damage

25
Q

What were the primary effects of the Icelandic Eruption (2010)?

A

Agricultural land destroyed by the ash
Ash contaminated water supplies
Flight paths were closed due to huge ash cloud

26
Q

What were the secondary effects of the Icelandic Eruption (2010)?

A

Airlines lost £130 million per day
Lots of stock could not be traded due to ash cloud
Tourism declined
Sports events cancelled

27
Q

What can scientists do to protect against volcanoes?

A

They can check for signs of an eruption (monitoring)

They can take action to prevent effects (protection)

28
Q

What three things do scientists use to monitor volcanoes?

A

Seismometers
Tiltmeters
Monitoring gases

29
Q

What is a seismometer?

A

This is a device that measures movements in the earth’s tectonic plates which can trigger an eruption

30
Q

What is a tiltmeter?

A

This is a device that picks up on any changes in the shape of the volcano. Swelling can indicate that magma is rising.

31
Q

Why do scientists monitor the volcano’s gases?

A

Volcanoes give off sulphur dioxide before erupting.

32
Q

What four things do scientists do to protect against volcanoes?

A

Land use zoning
Divert lava flow
Covers for gutters
Triple roof support

33
Q

Explain how land use zoning can protect against volcanoes

A

Putting more important building further away from the volcano

34
Q

Explain how diverting lava flow can protect against volcanoes

A

Lava can be slowed by blasting it with cold water

35
Q

Explain how covers for gutters can protect against volcanoes

A

It prevents them blocking with ash

36
Q

Explain how triple roof support can protect against volcanoes

A

Ash can weigh on roofs causing them to collapse

37
Q

What are convection currents?

A

Circulating movements of magma in the mantle caused by the heat of the core, causing tectonic plates to move

38
Q

What is the core?

A

The innermost part of the earth. It has two parts: the inner core (solid) and the outer core (liquid). It is 5500°C

39
Q

What is the mantle?

A

The molten rock layer between the core and the crust

40
Q

What are primary effects?

A

Impacts of a natural disaster that happen immediately after the event

41
Q

What are secondary effects?

A

The knock on effects of the primary effects e.g. homelessness due to houses being destroyed

42
Q

What are responses?

A

The way in which people react to a situation e.g. a natural disaster

43
Q

What is subduction?

A

Crust being forced down into the mantle