Global Hazards Flashcards

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1
Q

What is the Global atmospheric circulation at the Equator?

A

At the equator,the Sun warms the Earth,which transfers heat to the air above,causing it to rise.This creates a low pressure belt with rising air,clouds and rain.

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2
Q

What is the Global atmospheric circulation north and south of the Equator?

A

As the air rises it cools and moves out to the north and south of the equator.

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3
Q

What is the Global atmospheric circulation 30 degrees north and south of the Equator?

A

At 30 degrees north and south of the equator,the cool air sinks creating a high pressure belt with cloudless skies and very low rainfall.

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4
Q

What is Wind?

A

Wind is air moving from areas of high to low pressure.This means the atmosphere circulation causes winds,making some parts of the world windier than others.

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5
Q

Where is wind the strongest?

A

They are only strong between pressure belts.

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6
Q

Distribution of Temperature?

A

The equator receives the most energy from the sun. The poles receive the least. Temperature can be very high in high pressure areas.

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7
Q

When does precipitation occur?

A

Precipitation occurs when warm, wet air rises and cools causing water vapour to condense.
Air rises in low Pressure belts = Frequent precipitation.

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8
Q

When do Tropical Storms form?

A

Tropical storms develop when the sea temperature is 27 degrees or higher.
The warm ocean temperature means there is lots of warm,moist air to cause extreme precipitation.

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9
Q

What is Condensation?

A

Condensation when warm air rises and cools releases huge amount of energy,which makes the storms powerful.

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10
Q

Temperature UK vs Australia

A

Temperature:
Australia is warmer than the UK having hotter summers and milder winters.
Average temp for Australia is 33 Degrees,UK is 23 Degrees

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11
Q

Precipitation UK vs Australia

A

Precipitation:
Australia has a lower precipitation than the UK.
Average rainfall for Australia is : 465mm Uk is : 1150mm
Overall UK is more drier than Australia

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12
Q

Wind UK Vs Australia

A

Wind:
Australia has strong extreme winds than the UK.
Aus, is affected by tropical cyclones which cause these extreme winds.
Strongest wind recorded in Australia:400km/h UK:220km/h

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13
Q

How are extreme winds caused?

A

Strong winds in tropical storms are caused by an area of very low pressure at the centre of the storm that creates a big pressure difference.

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14
Q

How is Extreme rain caused?

A

This is caused by large amounts of warm,moist air being sucked towards the centre of the storm due to the difference in pressure.

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15
Q

Describe the distribution of storms?

A

Distribution of most tropical storms occur between 5* and 10* north and south of the equator.

The majority of storms occur in the northern hemisphere in late summer and autumn,when sea temperatures are highest

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16
Q

What is La nina and the process?

A

La nina is when the normal conditions become more extreme.
Trade winds blow to the west more strongly and more cold water rises.
It causes more heavy rainfall and floods in the west and less rainfall in the east and droughts.
Events occur every 2-7 years.

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17
Q

What is El Nino and the process?

A

Pressure rises in the west and falls in the east.
This causes the trade winds to weaken or reverse direction.
The sinking air in the high pressure = unusually dry weather.(West)
The rising air in the low pressure area = unusually wet weather.(East)

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18
Q

What is a Drought?

A

Drought is when conditions are drier than normal.
Drought is a long period when rainfall is below average.

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19
Q

What are the consequences of Droughts?

A

Water supplies become depleted during a drought because people keep using them but they aren’t replenished by rainfall.
Drought are often accompanied by high temperature which increases rate of evaporation,so water supplies are depleted faster.

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20
Q

What are the causes of Droughts?

A

Change in atmospheric circulation.

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21
Q

Causes of Hurricane Katrina (4)

A

1)Gulf of Mexico, where sea temperatures where 27 degrees, meaning tropical storms can form.
2)A storm formed 200 miles south-east and moved north-west.
3)As it travelled over the Gulf of Mexico, it became stronger.
4)On the morning of the 29th it struck.

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22
Q

Hurricane Katrina Characteristics:
1)Height 2)Wind Speed 3)Location

A

1)8.5m
2)200km/h
3)Mississippi

23
Q

Consequences of Hurricane Katrina (4)?

A

> More than 1800 people were killed
300K homes were destroyed and 100s and 1000s were homeless.
3 Million people were left without electricity
230K jobs were lost
The total cost of the damage was $150Billion

24
Q

Responses of Hurricane Katrina (4)?

A

> 75% of New Orleans were evacuated
The coastguard, police and army rescued over 50k people
Repaired and improved flood defences
Charities collected donation and provided aid.
US government provided over 16 billion dollars for rebuilding homes.

25
Q

Causes of Heat Wave

A

> An anticyclone was situated over western Europe for most of the August.
Air moves clockwise around an anticyclone,so dry air from the centre of the continent was brought to western Europe.
This mean the temperature of the UK was higher than normal and rainfall was lower than normal.

26
Q

Consequences of the heatwave

A

> People suffered heat stroke, dehydration, sunburn and breathing Problems
Around 2000 people died causes linked to the heatwave
Water levels fell in reservoirs. Which threatened water supplies.
Livestock died due to the heat and crop yields were lower
Trains were disrupted by rails bulking in the heat and some roads melted.

27
Q

Responses to the heatwave

A

> The NHS and the media gave guidance to the public on how to survive the heat wave e.g. drink lots of water and have cool baths.
Limitations were placed on water use
The UK created a heatwave plan to minimise consequences of future heatwaves.

28
Q

What is the inner core?

A

> A ball of solid iron and nickel.

29
Q

What is the outer core?

A

Liquid

30
Q

What is the mantle?

A

> Semi-molten rock that moves very slowly.

31
Q

What is the Crust

A

> Outer Layer of the Earth,about 10-70km Thick.

32
Q

Characteristics of continental crust

A

> Thicker and less dense

33
Q

Characteristics of continental crust

A

> Thicker and less dense

34
Q

Characteristics of oceanic crust?

A

> Thinner and more dense

35
Q

Describe the process of convection currents?

A

> The lower parts of the mantle are sometime hotter than the upper parts.
When these lower parts heat up they become less dense and slowly rise.
As they move towards the top of the mantle they cool down, become more dense, then slowly sink.

36
Q

What is a Destructive Boundary?

A

> When two plater are moving towards each other.
1)Where an oceanic plate meets a continental plate, the denser oceanic plater is forced down into the mantle and destroyed.

37
Q

What does a Destructive Boundary create?

A

> Volcanoes and oceanic trenches

38
Q

What is a Collision Plates Boundary?

A

> Both plater are made from continental and are moving towards each other
1)Neither plate is forced down into the mantle, instead they are folded and forced upwards.

39
Q

What does a Collision Plates Boundary create ?

A

> Fold Mountains

40
Q

What is a Constructive Boundary?

A

> Where two plater moving away from each other.
1)Magma rises from the mantle to fill the gap and cools, creating new crust

41
Q

What is a Conservative Boundary?

A

> Where two plates are moving sideways or in the same direction or at different speeds.
Crust isn’t created or destroyed.

42
Q

How are Earthquakes caused?

A

> Caused by tension that builds up at all four boundaries.

43
Q

Describe the process of Earthquakes?

A

The plates eventually jerk past each other, sending out shock waves.

44
Q

Shock Waves:

A

> The shock waves spread out from the focus-the point in the Earth where the earthquake starts.
Near the focus the waves are stronger and cause more damage.

45
Q

Epicentre:

A

> The epicentre is the point on the Earth’s surface straight above the focus.

46
Q

Shallow Focus:

A

> Shallow-focus earthquakes are caused by tectonic plates moving at or near the surface, they have a focus between 0km and 70km below the Earth’s surface.

47
Q

Deep-Focus:

A

> Deep-focus earthquakes are caused by crust that ha previously been subducted into the mantle moving towards the centre of the Earth,heating up or decomposing.

48
Q

How are hotspots formed?

A

1)A hotspot if a bit of earth’s crust that is hotter than normal.
2_They occur where a plume of hot magma move towards the surface, causing an unusually large flow of heat from the mantle to the crust.
3)Sometimes the magma can break through the crust and reach the surface, when this happens there is an eruption and a volcano forms.

49
Q

Characteristics of a composite Volcanoes:

A

> Occurs at destructive plate boundaries
Subducted oceanic crust contains lots of water, the water can cause the subducted crust to erupt.
The eruptions starts with ashy explosions that deposit a layer of ash,then erupt a layer of thick,sticky lava that can’t flow far.

50
Q

Characteristics of a composite Volcanoes:

A

> Occurs at destructive plate boundaries
Subducted oceanic crust contains lots of water, the water can cause the subducted crust to erupt.
The eruptions starts with ashy explosions that deposit a layer of ash, then erupt a layer of thick, sticky lava that can’t flow far.

51
Q

Characteristics of Shield Volcanoes:

A

> Occurs at hotspots
They aren’t very explosive and are made up of only lava
The lava is runny, it flows quickly and spreads over a wide area, forming a low, gentle sided volcano.

52
Q

Early Warning systems for Earthquakes:

A

> Early warning systems meaning that warnings can be communicated quickly to people, when shaking is detected, using the internet, SMS networks.
The warning is useful because:
.People can get undercover before shaking
.People doing delicate/dangerous jobs can get to safety
.Utilities can shut off
.Trains can start slowing down

53
Q

Predicting and monitoring volcanoes:

A

> Scientists can monitor the signs before a eruption this helps:
.Evacuation zones can be extended if the eruption becomes more violent.
.Ash clouds that can damage aircraft can be tracked, so flight can be diverted.
.If ash and poisonous gases spread, authorities can warn people to put on gas masks.

54
Q

Building Design:

A

> Building can be designed to withstand earthquakes, by using reinforced concrete.
Existing buildings and bridges can be strengthened.
Pipelines can be designed to flex and not break during earthquakes, this helps prevent deaths and damage to property by flooding.