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Geography > Natural Hazards > Flashcards

Natural Hazards Flashcards

1
Q

What is a natural hazard?

A

And event beyond human control that could threaten both life and property.

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2
Q

What are 9 natural hazards?

A
  • sandstorm
  • earthquake
  • tsunami
  • volcanic eruption
  • thunderstorm
  • landslide
  • drought
  • floods
  • tropical storm -> hurricane, typhoon, cyclone
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3
Q

What is a secondary hazard?

A

A secondary hazard is one that occurs because of another hazard e.g. a tsunami is caused by an earthquake

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4
Q

What are the human factors that affect the risk of natural hazards?

A
  • population density - how crowded, sparsely populated = fewer people so less risk (however getting help may be difficult), densely populated areas have more people so more risk (however emergency services can get you more quickly)
  • wealth - less money after to build, preparing buildings/earthquake resistant buildings are expensive
  • quality of building
  • politics - if war, then buildings already weakened, not enforcing regulations like building codes bc of corrupt government
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5
Q

What are the physical factors that affect the risk of natural hazards?

A
  • Location – more at risk from earthquakes if on a plate boundary
  • Frequency – lots of earthquakes means you may not have recovered from one before the next so risk is higher
  • Magnitude
  • Mountainous/rural – hard to get aid there
  • Time of day – if at night, difficult to rescue people or if in your house, it may collapse
  • Seasons – if it is cold or wet, those made homeless are more at risk
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6
Q

What are factors that affect volcano risk?

A

If there is…

  • no warning
  • no evacuation plan – chaotic response
  • buildings very close together
  • population density
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7
Q

What are factors that affect tropical storm risk?

A
  • no warning
  • no evacuation plan
  • population density
  • just above or below equator
  • time of day
  • frequency
  • very remote
  • lack of education on preparation
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8
Q

What is continental drift?

A

The theory that the earths crust is broken into large pieces called tectonic plates, moving a few centimetres each year

The continents that we know today used to be together and form one supercontinent called Pangea. Over time the plates have moved and the supercontinent broke up.

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9
Q

Who discovered continental drift?

A

Alfred Wegener

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10
Q

What are the 3 reasons that Wegener thought that continental plates were moving?

A
  • Jigsaw – the continents fit together like a jigsaw
  • Fossils – fossils of land animals were found in continents that were separated by the sea
  • Mountain ranges – when continents are placed together you can see mountain rages meet up
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11
Q

What is the structure of the earth?
(from the inside to the outside)

A
  1. Inner core - very hot, solid
  2. Outer core - liquid
  3. Mantle - semi liquid/solid
  4. Crust - rock, thin (7km - 70km deep)
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12
Q

What are properties of continental crust?

A
  • older
  • less dense (than oceanic)
  • thick (up to 70km)
  • mainly has landmass on it
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13
Q

What are the properties of oceanic crust?

A
  • younger
  • denser
  • thin (up to 10km)
  • mainly has ocean on it
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14
Q

What 3 things makes the plates move?

A
  1. Convection currents
  2. Ridge push
  3. Slab pull
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15
Q

Why do plates move?
(3 key learning points)

A
  1. Convection currents, move plates together or apart or slide them past each other
  2. At constructive plate boundaries, convection currents and ridge push move the plate apart
  3. At destructive plate boundaries, convection currents and slab pull move the plates together
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16
Q

How do convection currents happen?

A
  • In the core of the Earth, there is radioactive decay – this produces a lot of heat (7000°C)
  • The particles in the mantle close to the core get heated, so they rise
  • As the particles move away from the core, they cool down, and they become more dense so they sink
  • The crust will move along because the convectional current drags it
  • This movement is called a convection current
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17
Q

How does ridge push happen?

A
  • Plates move apart by convection currents
  • The crust is heated and expands so rises to form a slope
  • The crust cools down + becomes dense
  • The gravity + the weight of the plate also makes it move
  • This is called ridge push
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18
Q

What are the four types of plate boundaries?

A
  • constructive plate boundary <— —>
  • destructive plate boundary —\ <—
  • conservative plate boundary //
  • collision plate boundary —><— (don’t need this)
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19
Q

What happens at a constructive plate boundary?

A
  • Convection currents in the mantle cause hot magma to rise, heating the rocks above them 🔃
  • The tectonic plates move apart from each other because of ridge push, the molten magma rises in between, cools and forms new rock.
  • This forms part of the new oceanic plate.
  • The new plate sometimes fractures as it is moved, causing shallow, usually small, more nonviolent earthquakes.
  • Much of the magma never reaches the surface, but it can push the crust upwards to form ridge and rift features.
  • Where magma does erupt onto the surface it produces a lava that is runny and spreads out before solidifying.
  • This produces after many eruptions a shield volcano. 🌋
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20
Q

What happens at a destructive plate boundary?

A
  • At a destructive plate boundary plates move together because of convection currents in the mantle and slab pull
  • When they meet tension builds up in the plate
  • If the plates slip, then energy is released as seismic waves, causing an earthquake
  • At destructive plate boundaries oceanic plates meet continental plates
  • The oceanic plates subducts because it is denser
  • As it sinks into the mantle it melts forming magma
  • This magma is formed under pressure so forces its way through cracks in the rock above
  • So will explode at the surface as lava forming a violent composite volcano.
  • This causes hazards like lava flows and ash clouds 🌋
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21
Q

What happens at a conservative plate boundary?

A
  • Pressure builds up at the margin as the plates are being pulled along by a plate being moved by convection currents. Eventually, the pressure becomes too great, the rock fractures in an earthquake and jolts into a new position. (snag)
  • Land is neither created nor destroyed, and so there are no volcanoes.
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22
Q

What is an example of a constructive plate boundary?

A

The Mid Atlantic Ridge

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23
Q

What is an example of a destructive plate boundary?

A

The Pacific ring of fire

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24
Q

What is an example of a conservative plate boundary?

A

San Andreas Fault

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25
Q

What are the 2 types of crust?

A

oceanic + continental

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26
Q

What heats the mantle?

A

radioactive decay in the core

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27
Q

Why do the particles in the mantle rise?

A

they are heated and then they expand + become less dense

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28
Q

What type of crust is the densest?

A

Oceanic crust

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29
Q

What is the process where the oceanic crust goes under the continental crust?

A

Subduction

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30
Q

What type of volcanoes are found at destructive plate boundaries?

A

composite volcanoes

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31
Q

What type of volcanoes are found at constructive plate boundaries?

A

shield volcanoes

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32
Q

Which type of crust is younger?

A

oceanic

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33
Q

When plates are moving together what builds up in the rock?

A

elastic energy + pressure

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34
Q

Where do convection currents occur?

A

in the mantle

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35
Q

What is ridge push?

A

The process where the plates move because of gravity acting on the plate where it is forced up

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36
Q

What is slab pull?

A

It is where the plates move faster, because of the weight of the plate and gravity acting on the plate as it is subducted

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37
Q

What is a primary effect?

(give 3 examples)

A

They are the immediate impact caused by the hazard itself

e.g. death, buildings collapsing and injuries

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38
Q

What is a secondary effect?
(give 3 examples)

A

They happen later on often as a result of the primary effects

e.g. starvation, lower economy and spreading disease

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39
Q

What is an immediate response?

A

A response in the days and weeks immediately after a disaster has happened

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40
Q

What is a long-term response?

A

Go on for months and years after disaster

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41
Q

What is short term aid?

A

It is the aid that is given immediately (decreases secondary effects)

42
Q

What is long term aid

A

It is the aid that is given weeks or months after after the hazard and should help the country recover

43
Q

How many people died in the Nepal earthquake?

A

9,000

44
Q

How many buildings were damaged or destroyed in Nepal?

A

800,000

45
Q

What was the cost of the damage in Nepal?

A

$5 billion

46
Q

What percentage of Nepal’s GDP did the damage account for?

A

A third

47
Q

How many people died in New Zealand in the 2016 earthquake?

A

2

48
Q

How long was it before power was restored in New Zealand?

A

A few days

49
Q

How long after the earthquake was a new watermain built in New Zealand?

A

4 months

50
Q

What was the total cost of damage in New Zealand?

A

$8.5 billion

51
Q

What percentage of New Zealand’s GDP did the damage account for?

A

1%

52
Q

What are advantages of living in tectonic areas?
(shortened)

A

-geothermal energy⚡️ = lower energy bills💵 + good industry 🏭
-tourism 📸= money 💵
-ash good for soil 🌱 = good for farmers🧑‍🌾
-precious stones 💎 = jobs + money 💵

53
Q

What are disadvantages for living in tectonic areas?

A

-ash pollutes rivers 🏞️ = where locals get water 💧
- eruptions destroy houses 🏘️
- can be deadly 💀

54
Q

What are the things you can do to reduce the effects of tectonic hazards?

A
  • monitoring
  • prediction
  • protection
  • planning
55
Q

What is a Tropical Storm?

A

It is an intense low pressure system that is formed over tropical waters

56
Q

Where do Tropical Storms occur?

A

Either side of the equator - between 5 degrees and 20 degrees North and South

57
Q

What is an advantage of monitoring and prediction of tropical storms?

A

it gives people and governments enough time to take action (e.g. evacuation) to reduce the impacts of tropical storms and help protect lives

58
Q

What are advantages of protection against tropical storms?

A
  • reduces building damage if the protection is effective
  • if you use a sea wall, protects people living by the sea from sea surges
59
Q

What are advantages of planning for tropical storms?

A
  • training people + emergency services how to react reduces risk of chaotic response which can reduce no. of deaths
  • planning evacuation routes can allow people to get away from the storm quicker
60
Q

What is a fact that relates to monitoring + prediction from Typhoon Haiyan?

A

The government televised a warning for people to prepare and authorities evacuated 800,000 people

61
Q

What is a fact that relates to protection from Typhoon Haiyan?

A

After Typhoon Haiyan, in July 2014, the government declared a long term recovery plan called ‘Build Back Better’ where buildings were upgraded to be better at withstanding tropical storms

62
Q

What three things does a tropical storm need to form?

A
  1. Warm sea (27°C or more)
  2. Low pressure
  3. Coriolis effect
63
Q

Which way do winds bend in the northern hemisphere?

A

To the right

64
Q

Which way do winds bend in the southern hemisphere?

A

To the left

65
Q

How does a tropical storm form?

A
  1. Hurricanes draw the energy from warm seas and can only occur over areas of warm water 27°C or more.
  2. Because the surface water is very warm it evaporates, rises and condenses into storm clouds.
  3. The rising air creates low pressure which pulls surface winds in from the edges of the storm.
  4. Where “vertical wind shear” is low, the clouds are prevented from breaking up as they rise. (vertical wind is the when the top and bottom of the storm have different speeds/times they are spinning in??)
  5. The storms spin because of the Coriolis effect.
  6. As the storm moves over the ocean the energy from the warm water strengthens the storm so the wind speeds increase.
66
Q

Why do Tropical Storms die out?

A
  1. When they hit cold water they lose their energy source (warm water) and so begin to die out
  2. As they pass over land, friction slows them down
67
Q

How will climate change affect tropical storms’ frequency?

A

Oceans or stay at 27°C for longer, so may mean that there are more storms as there is a longer time when they can form.

e.g. in the Atlantic the number of tropical storms has increased each decade

68
Q

How will climate change affect tropical storms’ distribution?

A

As temperatures rise, more areas might be 27°C or more, so they may occur in more areas

69
Q

How will climate change affect tropical storms’ strength?

A

Higher sea surface temperatures means
More evaporation
SO
More cloud formation
SO
More energy
SO
Storms could be more powerful

e.g. intensity expected by 2-11% by 2100

70
Q

What are the social effects of extreme weather in the UK?

A
  • Death and injury (not very common)
  • Inability to travel (limits education)
  • Freezing pipes (stops water and heating)
  • Damage to buildings and property
  • Flooding
  • Lower quality of life
  • Reduces tourism (storms) or increases tourism (heatwave)
71
Q

What are the economic effects of extreme weather in the UK?

A
  • Energy bills rise (to heat or cool your house)
  • Businesses are forced to close
  • Repairs to housing and replacing property if no insurance
  • Loss of income.
72
Q

What is the short term evidence for climate change?

A
  • Recordings of global temperatures by Met Office, using weather station satellites etc
  • Photographs + recordings of shrinking glaciers
  • Recordings of sea levels
  • Old photographs and paintings and historical documents
73
Q

What is the long-term evidence for climate change?

A
  • Ice cores
  • sediment cores
  • tree rings
  • pollen samples
74
Q

How do sediment cores work/what are they?

A
  1. Overtime, the ocean has been warmer and colder
  2. Different animals and plants, live in different temperatures and seas
  3. Different sediments fall to the bottom of the sea and over time they form different layers
  4. Then scientists analyse each layer to see the types of sea life and then work out if the sea was warm or cold
75
Q

How do Tree rings work/what are they?

A
  • Warmer times trees grow more, so the rings are thicker
  • Colder times trees grow less, so the rings Are thinner
76
Q

What are pollen samples/how do they work?

A
  • You find it in peat bogs
  • They are wet environments, so living matter decomposes, very slowly.
  • Scientist can analyse the type of plant and therefore what the temperatures were so we can collect ancient pollen samples.
77
Q

What are the natural causes of climate change?

A
  • Orbit changes
  • solar output
  • volcanic activity
78
Q

What are orbit changes?

A
  1. Every 100,000 years, the Earth changes from an elliptical (oval) to a circular orbit
  2. When it is oval, it is warmer and interglacial
  3. when it is circular it is colder and a glacial

way to remember: Circular - C - Cold circular

79
Q

What is solar output?

A
  • Sunspots are dark spots on the Sun surface that radiate out more energy, making the Earth warmer.
  • They follow irregular circle
  • They last about 11 years
  • We have currently had 50 years of low solar activity.
80
Q

What is volcanic activity? (in terms of causes of climate change)

A

Major volcanic eruptions lead to a brief period of global cooling
e.g. ash and SO2 blocks the Sun

81
Q

What are human causes of climate change?

A

Since industrial revolution - but only getting very bad in 1960 - as more of the world industrialised more cars, more planes and we ate more cows and cut down more trees

The greenhouse gas layer has got thicker
SO it traps more heat so the temperature of the earth is increasing

82
Q

What are some effects of climate change on people?

A
  • Deaths due to changing temperature
  • In some areas are hard or impossible to inhabit
  • Some areas are struggling to supply enough water
  • Some crops are suffering and has caused smaller yields
  • Some crops are benefiting due to warmer conditions
  • Lower crop yields could Increase malnutrition, ill health and death from starvation
  • The weather is getting more extreme so more money has to be spent on predicting extreme weather events
83
Q

What are some effects of climate change on the environment?

A
  • Warmer temperatures = glaciers to shrink and ice sheets to melt so sea levels are rising
  • Sea ice is also shrinking leading to the loss of polar habitats
  • Rising sea levels mean low-lying in coastal areas will flood more regularly and coastal erosion will increase
  • Other species are declining due to warming , e.g. coral reefs 🪸are suffering from bleaching
  • Precipitation patterns are changing
  • The distribution and quantity of some species could change + biodiversity could decrease
  • Habitats are being damaged or destroyed and have to live it higher latitudes (further from the equator) due to warming temperatures
84
Q

What are the 2 ways to cope with climate change?

A

Mitigation and adaptation

85
Q

What is mitigation?

A

Aims to reduce the cause of the problem by limiting or preventing GHGs and protecting carbon sink (e.g. trees)

86
Q

What is adaptation?

A

Responds to the impact of climate change and tries to make people less vulnerable

87
Q

What are the four mitigation strategies?

A
  • Wind/solar energy
  • Carbon capture
  • Planting trees
  • International agreements
88
Q

What are the three adaptation strategies?

A
  • Changes in farming
  • Managing water supply
  • Reduce risk from sea level rise
89
Q

How does wind/solar energy reduce climate change?

And a fact that goes with it?

Assessment?

A

Renewable sources of energy do not produce CO2, so there is less CO2 in the atmosphere, so the greenhouse gas layer will not get thicker

In 2022 36% of the U.K.’s electricity was generated using renewables

  1. They are good, but they are more expensive than fossil feels although they are coming down in price
  2. If there is no sun or wind you need an alternative source
90
Q

How does carbon capture reduce climate change?

A fact that goes with it?

Assessment?

A

Stops CO2 from being emitted by power stations, catches it and taken underground or used for something else. So less goes in the atmosphere

In 2021 44 MT (mega tonnes) of CO2 was captured globally

  1. It isn’t used very much as it is very expensive
  2. it is part of the solution, but it isn’t the only thing
  3. we don’t know the future impact of storing it
91
Q

How does planting trees reduce climate change?

And a fact that goes with it?

Assessment?

A

Trees absorb CO2 so there is less CO2 in the atmosphere. With more trees, more CO2 will be absorbed

If we planted 25% more of forest we already have that would absorb 25% of all CO2 in the world.

  1. It is great but there is not much/not enough space
  2. They take a long time to grow.
92
Q

How do international agreements reduce climate change?

And a fact that goes with it?

Assessment?

A

Large conferences where governments from all countries make pledges and agreed to reduce their carbon emissions (CO2)

196 parties at COP 21 in Paris signed a legally binding treaty on Climate Change.

  1. It is difficult to get countries to stick to it
  2. if countries only have bigger priorities e.g. war they would focus on that instead.
93
Q

How do changes in farming help people adapt to climate change?

And a fact that goes with it?

Assessment?

A

There are two main methods:
Floating gardens - where farmers can still grow food/crops, but on top of water, so when it floods or rising sea levels won’t affect it
Tolerant + resistant seeds to drought conditions have been invented

With floating gardens, farmers can earn an average profit of $140 per square metres during the monsoon season.

  1. Floating gardens are cheap, easy and efficient (not really any disadvantages)
  2. The seeds are quite expensive.
94
Q

How does managing water supply help people adapt to climate change?

And a fact that goes with it?

Assessment?

A

There are two main methods:
Drip irrigation is where there are pipes in the ground right next to the seeds slowly feeding it water so less water is wasted.
Hydroponics is when you grow plants in greenhouses in tubes with very little water.

Hydroponics takes 10x less water than regular plants.

  1. Good ways to manage water
  2. Drip irrigation isn’t expensive.
  3. Hydroponics is very expensive.
95
Q

How does reducing risk from sea level rise help people adapt to climate change?

And a fact that goes with it?

Assessment?

A

Either building a flood barrier to stop flooding or build houses on stilts.

The Thames barrier has been closed 200 times to prevent flooding

  1. Barriers are very effective, but very expensive
  2. Houses on stilts are good and cheap, but if water rises too much, it is ineffective.
96
Q

What are the things you can do to reduce the effects of tectonic hazards?

A
  • monitoring
  • prediction
  • protection
  • planning
97
Q

What is the definition of prediction?

A

attempts to forecast when and where a natural hazard will strike

98
Q

What is the definition of monitoring?

A

recording physical changes to help forecast when and where a natural hazard will strike

99
Q

What is the definition of protection?

A

actions taken before a hazard strikes to reduce it’s impacts

100
Q

What is the definition of planning?

A

actions taken to enable communities to respond to, and recover from, natural disasters

Geography (6 decks)

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