Topic 1 : Hazardous Earth Flashcards

1
Q

Name the parts of the Earth

A

Crust
Mantle
Outer core
Inner core

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2
Q

Name the two parts of the upper mantle

A

Lithosphere and asthenosphere

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3
Q

What is the outer core made of?

A

Iron and nickel

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4
Q

Name the plate boundaries

A

Divergent
Convergent
Conservative
Collision

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5
Q

What happens in divergent plate boundaries?

A

Plates move apart

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6
Q

What happens in convergent plate boundaries?

A

Plate moves under the other

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7
Q

What happens in a conservative boundary?

A

Plates slide past each other

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8
Q

What happens in a collision boundary?

A

Plates move towards each other

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9
Q

What are tectonic plates?

A

The earth’s surface broken into large pieces

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10
Q

What is radioactive decay?

A

Atoms of radioactive elements release particles from nuclei and give off heat

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11
Q

Describe oceanic crust

A

Very thin
Made of basalt
Thin but more dense

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12
Q

Describe continental crust

A

Low density
Made of thick granite
Thick but less dense

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13
Q

How do earthquakes happen?

A

Tectonic plates move
This is concentrated along fractures
Friction builds up against plate boundary until energy is released
This energy is sent out as seismic waves

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14
Q

What is the epicentre?

A

The point on the Earth’s surface above the focus

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15
Q

What are seismic waves?

A

Earth’s energy being released

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16
Q

What is the focus?

A

Point inside the crust where pressure is released

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17
Q

What are hotspot volcanoes?

A

Warm areas in the mantle where heat moves up and forms in the middle of a plate

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18
Q

What causes a tsunami?

A

Destructive/convergent wave plate movement causes earthquake
Sea above is forced upwards
This movement causes tsunami
Seismic waves spread and waves crash onto shore

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19
Q

What is climate?

A

Average weather over 30 years

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20
Q

What are ocean currents?

A

a continuous, directed movement of sea water generated by a number of forces acting upon the wate

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21
Q

What is a Hadley cell?

A

The largest cell

Warns air rises out the equator and travels around 30 degrees north where it cools and sinks

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22
Q

What is a Ferrel cell?

A

Smaller cell
Found between Hadley and Polar
Powered by other two cells

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23
Q

What is a Polar cell?

A

Smallest cell

Cold air sinks at North Pole and warms

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24
Q

What are differences in climate caused by?

A

Gulf Stream

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25
Q

How can we learn about past climate?

A

Historical sources
Ice cores
Tree rings

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26
Q

What is the Greenhouse effect?

A

Warming of Earth’s surface and the air above it. It is caused by gases in the air that trap energy from the Sun

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27
Q

Describe the pressure over land

A

Land heats the air above which expands and becomes tighter and rises
Forms are of low pressure in the summer
and in the winter high pressure

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28
Q

Describe the pressure over sea

A

Sea takes longer to heat and cool, the air above dense
High pressure in the summer
Low pressure in winter

29
Q

Describe pressure over wind

A

Created when air moves from high to low pressure

30
Q

Describe the process of ocean current formation

A
Cold, salty water sinks 
Creates a convection current
Drags water down
Warmer water is drawn from the equator 
Cool air sinks
It flows south to the equator and is warmed again
31
Q

Why is heat distributed around the Earth?

A

Because it’s to pressure difference and ocean currents

32
Q

What is ITCZ?

A

Inter-TropicL Convergence zone

33
Q

Describe characteristics of the ITCZ

A
Part of global circulation model
Forms within the tropics
Forms when 2 air masses meet
Created within the Hadley cell
Area of low pressure and stretches around the Earth and brings rain
34
Q

Describe characteristics of a Hadley cell

A

Caused by heating + cooling
Creates low and high pressure
Consists of 2 parts - 1 on either side of the equator
Both parts move together as the Sun moves overhead seasonally

35
Q

Name the 5 main stages of ITCZ

A

Land warms air - expands becomes lighter + rises
Cooler high pressure air forms as the sea is cooler than the land
Trade Winds blow from high to low pressure towards the Southern Sahara
High pressure forms over Atlantic Ocean because sea is cooler than land in northern hemisphere summer
Trade Winds blow south, drawn by low pressure at ITCZ
Water vapour condenses to make rain

36
Q

Describe the crust of the Earth

A

50km thick
5 - 70 km thick
Solid rock

37
Q

Describe the Earth’s mantle

A

2900km thick
Upper mantle - lithosphere + asthenosphere
Lithosphere - close to crust, more liquid
Asthenosphere - underneath lithosphere, less liquid
Lower mantle - reaches to outer core

38
Q

Describe the Earth’s outer core

A

2266 km
4000 - 5700 degrees Celsius
Made of iron and nickel

39
Q

Describe the Earth’s inner core

A

Solid - iron and nickel

Same temperature as surface of the sun

40
Q

The moving of the Earth’s crustal plates are due to what?

A

Convection currents

41
Q

Where do convection currents occur?

A

In the mantle

42
Q

Explain why the Earth’s crust is unstable

A

Due to the mantle - the upper mantle has a lithosphere which is more liquid and closer to the crust and also has an asthenosphere which has some liquid underneath, making the crust unstable so when liquid is heated it causes movement
Due to convection currents - created by heat from within the Earth and are the cause of the movement of the Earth’s crustal plates

43
Q

Why do not all volcanoes form at plate boundaries?

A

Because there are cracks in tectonic plates

The magma and the mantle then rises to form a volcano

44
Q

How do earthquakes happen?

A

Movement of Earth’s tectonic plate
Concentrated along fault lines (fractures in Earth’s crust’
Friction builds up along plate boundaries as they move against each until energy is released
This energy is sent out as seismic waves

45
Q

How is a tsunami formed?

A

Destructive/ convergent plate movement causes earthquake
Sea above earthquake is forced upwards
Sea movement causes a tsunami
Seismic waves spread quickly
Waves crash onto shore devastating low lying area

46
Q

Explain differences between shield and composite volcanoes

A

Plate boundaries - shield is found on divergent plate boundary
Composite is found on convergent plate boundary
Lava - composite has layered lava which is very sticky
Shield has runny lava

47
Q

Explain how ocean currents can influence climates

A

By moving cold and warm water around the globe. Currents carry warm water from the tropics towards the poles and bring water back toward the equator which makes the ocean cooler
OR
By affecting temperature. The constant cycling of water helps moderate temperatures across the planet, by creating ocean temperature variations that less extreme than those found on land

48
Q

What is low pressure?

A

Warm air rises in areas of low pressure

As it rises and cools, water vapour condense to form clouds precipitation

49
Q

What is high pressure?

A

As air is heated at the equator, it rises and begins to descend at around 30 degrees latitude and the air is cooled

50
Q

Does air rise or sink in low pressure?

A

Rise

51
Q

Does air rise or sink in high pressure?

A

Sinks

52
Q

What is the ITCZ?

A

Zone of convergence at the thermal equator where the trade winds meet
It is a low pressure belt and migrates with the changing position of the thermal equator

53
Q

Explain why some areas in Africa are desert and some are tropical rainforest

A

Pressure belts - a low pressure belt between 0 and 30 degrees causes rainfall which is why some areas are tropical rainforest
High pressure belts bring dry climates due to the air sinking which why some areas are desert

54
Q

What is climate?

A

Average weather over 30 years

55
Q

What is the greenhouse gas effect?

A

The way that gases in the atmosphere trap heat from the sun

The gases let heat in but prevent most of it from getting out

56
Q

Describe the greenhouse effect process

A

Short wave radiation passes through the atmosphere
Some short wave radiation is absorbed and converted into Long wave radiation
Some long wave radiation passes back into space
Some long wave radiation is reflected off greenhouse gases back to Earth and heating Earth

57
Q

Explain one difference between the oceanic and continental crust

A

Oceanic crust has a higher density compared to continental which has a lower density
Continental crust is 30-50 km thick and oceanic is 6-8 km thick

58
Q

Explain why earthquakes happen on collision plate margins

A

Plate boundaries move towards each other
The collision plate margins move towards each other and this movement of colliding causes the friction to build up against each other which releases energy out into seismic waves

59
Q

What is a destructive plate margin?

A

When two tectonic plates move towards one another. The oceanic crust is forced to sink back into the mantle, whilst the continental crust rises above. Volcanoes and earthquakes are found here

60
Q

Where was Haiti Earthquake located?

A

Haiti
Between Caribbean and North American plates
Occurred on a destructive plate margin
25 km away from capital - Port au Prince

61
Q

State 5 key facts about Haiti earthquake

A
Magnitude - 7
Occurred on 12th January 2010 - 4:53pm
Conservative plate boundary 
Epicentre was 25km from Port au Prince
250,000 people died
62
Q

State primary effects of Haiti earthquake

A

Roads blocked
No telephone system - no internet or mobile phone signal
Key government buildings destroyed
Hospitals destroyed

63
Q

State secondary effects of Haiti earthquake

A

Cholera outbreak due to poor sanitation
3,000 temporary tent schools set up
Mass graves dug
1.5 million people sleeping in shelters

64
Q

State immediate responses from Haiti earthquake

A

Health care supplies provided to limit disease

National government began coordinating humanitarian aid

65
Q

State long - term responses from Haiti earthquake

A

Water and sanitation eventually supplied for 1.7 million people
$100 million in aid by US
$330 million by European Union

66
Q

Explain one way in which the global atmospheric circulation determines the location of high rainfall (low pressure) areas

A

The ITCZ/equator is a low pressure area with high rainfall - here warm air rises + cools as clouds are created
A further area of low pressure found at around 60 degrees north and south of equator
Warmer air rises as it meets colder air + water vapour condenses
At equator less dense air rises, cools and condenses giving rain

67
Q

Why 3 things causes places near the Equator to be much warmer than places near the Poles?

A

This is due to a combination of:
the curvature of the Earth
angle of the sun in the sky
layer of atmosphere surrounding Earth - contains smoke particles that absorb heat

68
Q

Why are places near the Equator much warmer?

A

At the equator the sun is at a high angle and shines vertically downwards
Heat is concentrated in a small area, resulting in it rapidly becoming hot
Solar radiation passes through atmosphere at a direct angle so less heat is lost