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Natural Hazards Flashcards

1
Q

What are the 4 different plate margins called

A

Destructive, constructive, conservative, collision

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2
Q

When does a constructive plate boundary occur

A

When two plates move away from each other
Convection currents moving in opposite directions in the mantle move the two plates apart
Magma will rise up and form a shield volcano
Erupts and then cools as new land, this can create huge ridges of undersea mountains
Two oceanic plates

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3
Q

When and what makes a destructive plate boundary occur

A

Usually involve an oceanic and a continental plate
Plates move towards one another

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4
Q

Process that occurs at a destructive plate margin

A

-Plates collide
-oceanic plate is forced under the continental plate because of subduction
-the plate sinks into the mantle to form magma
-pressure of magma builds up and escapes through weaknesses in the rock and rises and through a composite volcano
-eruptions are violent with lots of steam and ash

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5
Q

Why does subduction occur in a destructive plate margin

A

Because the oceanic plate is denser than the continental plate

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6
Q

What happens at a conservative plate margin

A

Plates move past each other and different speeds
As the plates move friction occurs and plates become stuck
Pressure builds as plates try to move when pressure is released it sends our huge amounts of energy causing an earthquake

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7
Q

Why can conservative plate margins be so destructive

A

They occur close to the earths surface

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8
Q

What happens at a collision plate margin

A

Two continental plates collide
Neither can sink and so the land buckets upwards to form fold mountains
Earthquakes can also occur

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9
Q

What are the two types of crusts

A

Oceanic and continental

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10
Q

What is oceanic crust

A

found underneath the oceans. It is denser than continental crust and can be subducted.

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11
Q

What is continental crust

A

found under land masses or continents. It is generally older than oceanic crust and is less often destroyed.

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12
Q

Where are earthquakes found along

A

All types of plate margins

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13
Q

Where are volcanoes formed along

A

Only occur at constructive and destructive plate margin

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14
Q

Factors affecting the risk of natural hazards

A

Urbanisation
Poverty
Location
High population density

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15
Q

Examples of atmospheric hazards

A

-storms
-tornadoes
-droughts

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16
Q

Definition of natural hazard

A

A natural event or phenomenon that poses a threat to human life or has a social impact

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17
Q

Example of hydrological hazards

A

-floods
-tsunamis
-storm surges

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18
Q

Example of geological hazards

A

-earthquakes
-volcanic eruption
-avalanches

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19
Q

What was alfred wegners theory

A

About continental drift that there was once a huge super continent

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20
Q

What was the evidence for Alfred wegners theory

A

-all continents fit together
-plant and animals were all across the world
-same geological structures across continents

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21
Q

What is a rift valley

A

Forms when earths tectonic plates move apart so river or sea forms

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22
Q

Name the 4 layers of the earth

A

Crust, mantle, outer core, inner core

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23
Q

What is the temperature of the core

A

Around 5500 degrees

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24
Q

Characteristics of continental crust

A

Granite rock type
Light
Old
Less dense
Found on land

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25
Characteristics of oceanic crust
Basalt rock type Found under seas Young Dense
26
What is year was the chile earthquake
2010
27
What year was the Nepal earthquake
2015
28
What was the magnitude of the chile earthquake compared to the Nepal earthquake
Chile = 8.8 Nepal = 7.9
29
What was the cost of the chile earthquake compared to the Nepal earthquake
Nepal = 5 billion dollars Chile= 30 billion dollars
30
How many people were killed in Nepal compared to the chile earthquake
Nepal = 9000 Chile = 500
31
What other natural hazard did the Nepal earthquake trigger
Landslides and avalanches blocking roads
32
What other natural hazard did chile earthquake trigger
Tsunami
33
Level of income of Nepal vs chile (GNI)
Chile = 14,100 dollars Nepal = 970 dollars
34
Features of a composite volcano
Tall coned Thick lava Narrow base Less frequent More explosive
35
Features of a shield volcano
runny lava Dome Less explosive Wide base
36
Chile immediate and long term responses :
Immediate = raised 60 million dollars which was enough to build 30,000 small emergency shelters Long term = a month after a housing reconstruction was put in place by the government to help nearly 200,000 households
37
Immediate and long term responses of Nepal earthquake:
Immediate = half a million tents provided to shelter for homeless, search and rescue teams lifted rubble, used camera Long term = roads were repaired and landslides cleared, held an international conference to discuss reconstruction and seek financial and technical support with other countries
38
Impact of eyjafjallajokul volcanic eruption
Havoc on European flight path (100,000) flights cancelled Homes and roads damaged
39
What is a tilt meter
A sensitive instrument that can detect changes to the tilt of earth We are able to see every change in the plates and detect if their are any seismic waves Also monitors levels of gas around a volcano
40
Why live near a volcano
Mining, heating, tourism, farming and soils
41
Ways to predict natural hazards
Seismometer = pick up vibrations at earths crust Heatseeking cameras = to see volcanic heat Tilt meters = measure earths movement Find water which is 27 degrees as this could cause tropical storm
42
Ways to protect against natural hazards
Shock absorbers for earthquakes Roads and buildings can be built to withstand power of earthquakes
43
Ways to plan for a natural hazard
Earthquake drills are held in schools Put together emergency kits and store them at home or work
44
Evidence for climate change
Rising sea levels Temperature Glacial retreat / melting ice Historical evidence from ice cores (to show greenhouse gases concentrations have changed in the past)
45
How much has sea levels risen
Between 10 and 20 cm
46
What is the quaternary period
Geological period that covers the last 2.6 billion years
47
How is glacial retreat evidence for climate change
-photographic evidence shows that the worlds glaciers have been melting causing them to retreat
48
How is ice cores evidence for climate change
-ice cores detects changes in temperatures -these ice cores go as far back as 400,000 years ago -and concentration of greenhouses gases can be seen
49
What is the enhanced greenhouse effect
-we are producing more greenhouse gases -so more heat reflected into atmosphere -and less heat will escape into space so it’s trapped -this will result in earth heating up quicker
50
What percentage of animals are at risk of extinction due to climate change
8 percent
51
How much ice has Antarctica lost compared to 25 years ago
3 times as much
52
Impacts of climate change
-Lower level of rainfall and high temperature -Longer food growing seasons -countries could become underwater due to river and sea levels
53
Positives to using fossil fuels
Generate large amounts of energy quite cheaply Locating where fossil fuels are is easy Means for extracting fossil fuels already exist
54
Negatives of fossil fuels
Suppliers are running out and new courses are harder to get to Release carbon dioxide contributes to global warming and greenhouse effect Oil spills can cause environmental damage
55
What is afforestation
Growing and planting of tress
56
Challenges to afforestation
Takes 20-40 years to actually absorb a significant amount of carbon Expensive Some climate can’t have trees
57
What is carbon capture
Carbon is collected and is injected deep into the ground after it is compressed turning it into a liquid, its injected into porous rock that carbon fills and has an impermeable layer that acts as a cap to prevent it from moving
58
Advantages of carbon capture
Allows up to 90% of carbon dioxide to be caught Reduces the carbon emissions of fossil fuel power plants
59
Disadvantages of carbon capture
Concerns around safety due to possibility of leakages and environmental contamination Large amounts of excess energy required to produce the equipment needed Earthquakes might result in co2 leakages
60
Ways to protect homes from natural hazards
Raised on stilts Paint white so heat is reflected Green roofs to reduce heat Aerodynamic
61
Natural causes of climate change
-volcanic eruptions -sunspot theory -eccentricity orbital theory -axial tilt orbital theory
62
How does volcanic eruptions cause climate change
Can emit lots of ash sulfur dioxide which prevents solar energy reaching earth which lowers the temperature
63
How does the sunspot theory cause climate change
They are dark spots on the earth that give off more solar energy (heat)
64
How does eccentricity orbital theory cause climate change
Earths orbit turns from a circle to an oval every 100,00 years so that means earth is further from sun so less heat from sun
65
How does axial tilt orbital theory cause climate change
Earths tilt changes every 4000 years this means that earths seasons could be shortened or extended
66
Human causes of climate change
Burning fossil fuels Agriculture Deforestation
67
How is high pressure formed
-air that is sinking towards the ground surface forms areas of high pressure
68
How is low pressure formed
Air that is rising from the ground surface forms low pressure. Winds on the ground move towards these areas of low pressure
69
Name the types of cells in global atmospheric circulation
Polar cell = at the north and South Pole Ferrel cell = between polar and Hadley cell Hadley cell = between equator and Tropic of Cancer / Capricorn
70
How does atmospheric circulation system explain the UKs mild cloudy and wet weather
-uk is located just below 60 degeees line of latitude -Uk is close to boundary of cold polar air moving down from north and warm sub tropical airs moving up from the south -there is rising air and low pressure belts -rising air cools and condenses forming cloud and rain
71
How does global circulation affect the worlds weather
-the circulation cells, pressure belts and surface winds affect the weather around the world -for exemplary the trade winds in the tropics are responsible for driving tropical storms
72
Characteristics of warm air
-it’s less dense -rising air -low air pressure -air cools and form clouds -warm air rises and holds lots of moisture
73
Characteristics of cold aid
-more dense -sinking air -high air pressure -clear sunny skies no clouds -little moisture in air
74
Why is there high rainfall at the equator
High solar energy radiating and heating the ground Air gets heated so then rises Air cools down condenses and forms clouds then it rains
75
Key conditions needed to form tropical storms
Warm oceans (over 27 degrees) Low pressure Light cross winds to begin with
76
How do tropical storms form
-Ocean water evaporates, the warm moist air rises creating an area of low pressure -air cools and condenses and forms clouds -air begins to spin because of the rotation of the earth -spinning storm is carried across the ocean as it moves across warmer ocean it becomes stronger
77
What is the Coriolis effect
The Coriolis effect makes storms swirl clockwise in the Southern hemisphere and counterclockwise in the Northern Hemisphere.
78
Primary effect of beast from the east snow storm
50cm of snow fell
79
Secondary effect of beast from the east
Snow melt and high tides caused flooding
80
Responses to the beast from the east
Royal air force was drafted in to help relief efforts in snow
81
Weather events that could effect the UK
Flooding (heavy rainfall) Extreme cold (low pressure) Drought (high temp) Storms (strong winds)
82
Primary effects of typhoon haiyan
-29,000 people died -cost damage of 12 billion dollars -roads were blocked -homes destroyed
83
Secondary effects of typhoon haiyan
-education disrupted as schools destroyed -airport badly damaged -flooding caused landslides
84
Immediate responses to typhoon Haiyan
- over one million food packs distributed -televised warning
85
Long term responses to typhoon haiyan
-upgraded damaged buildings with build back better campaign -Oxfam replaced fishing boats
86
How are tropical storms measured
Saffir Sampson scale
87
How does the Saffir Sampson scale measure tropical storms
Rating 1-5 based on wind speed, category 5 being the most dangerous with wind speeds of over 157
88
What was the wind speeds of typhoon haiyan
305 km/h
89
How can you monitor for tropical storms
Check for areas of low pressure and sea temperatures of 27 degrees
90
What is slab pull
as the crust subducts into the mantle gravity will pull the plate further into the mantle. The weight of the plate behind it will also push it down further
91
What is ridge push
The warm magma rises from the core and will PUSH the plates at the top upward (ridge push) as the plates stop the material rising further. This means the magmal then moves out sideways taking the crust along with it. The magma begins to cool at the surface of the mantle before sinking back down to the bottom to be heated again.
92
How do convection currents work
When magna nearest to the core of the earth is warmer and so less dense. This will result in it rising. The magma nearest to the crust is cooler and more dense and will sink. This repetitive cycle is convection currents
93
What is atmospheric circulation
Air from the equator rises and moves towards the poles, then cools down and sinks at approximately 30 degrees north and south of the equator. The sinking air creates an area of high pressure with very little rainfall. Some of the air moves back to the equator as surface winds called trade winds
94
Effects of boscastle flooding
80 homes destroyed Coastal pollution
95
Response management to boscastle flooding
Deepened and widened river, created natural wetland, rebuilt bridges and homes
96
Describe the link between air pressure and surface winds
Winds blow from high to low pressure. The trade winds blow from 30 degrees N and S towards the equator

Geography (10 decks)

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