Natural Hazard Flashcards
1
Q
What is a Natural Hazard?
A
Natural hazards are extreme natural events that can cause loss of life, extreme damage to property and disrupt human activities.
2
Q
What are the different types of Natural Hazards?
A
- Volcanic Eruptions
- Earthquakes
- Storms
- Tsunamis
- Landslides
- Floods
3
Q
What is Hazard Risk?
A
The chance or probability of being affected by a natural event.
4
Q
Why do people live in ‘Hazard Risk’ areas?
A
Natural Hazards do not happen regularly, so they decide to take the risk.
- Some people have little knowledge about where they’re living being dangerous.
- People may have little choice on where they can live
5
Q
What factors affect Hazardous Risk?
A
- Urbanization
- Climate Change
- Farming
- Poverty
6
Q
How does poverty affect hazardous risk?
A
- In poorer countries people are forced to live in Hazardous areas.
- Infrastructure in poorer areas makes them prone to maximal effect from the Hazard.
7
Q
How does farming affect hazardous risk?
A
-Rivers flooding leave fertile slit which is good for farming,
8
Q
How does Climate change affect hazardous risk?
A
- If a hot place becomes warmer, more energy in the atmosphere= more intense storms and hurricanes
- Places can become wetter leading to an increased risk of flooding
- PLaces can become drier, leading to drought and famine
9
Q
How does urbanisation affect hazardous risk?
A
- 50% live in cities making the population density in the area very high, therefore if a natural hazard occured the citizens and city is at major risk
e. g. Hati over 230,000 dead
10
Q
Where do earthquakes usually occur?
A
-On plate margins, where plates are moving and enormous pressures are built up and released
11
Q
What is another less common cause of earthquakes?
A
Human activity- underground mining or oil extraction
12
Q
What are the two types of crust?
A
Dense oceanic crust
Less dense continental crust
13
Q
How do plates move?
A
Move in relation to each other due to convection (heat) currents deep within the Earth
14
Q
Where do volcanoes happen?
A
-On long belts that follow plate margins e.g. pacific ring of fire
15
Q
Why is there a pattern of volcanoes?
A
- Volcanoes feed on hot molten rock (magma) from deep within the Earth.
- The magma rises to destructive and constructive plate margins where there are hot spots which is where the crust is weak so it can break through to form a volcano/erupt
16
Q
What happens at a constructive plate margin?
A
- Two plates move apart
- This allows magma to rise and force its way up
- When it breaks through the crusts hot spot it causes an earthquake
- When the magma reaches the surface it forms a flat shield or broad volcano
- The Lava which erupts will flow far before cooling as its very hot and fluid
17
Q
What happens at a destructive plate margin? (oceanic and continatal plate)
A
- Two plates move towards each other
- Where the plates meet, a ocean trench is formed
- The denser oceanic plate subduct’s beneath the less dense oceanic plate
- The friction caused between both plates cause an earthquake
- The oceanic plate moves downwards and melts forming magma which breaks through the crust to form a composite volcano
- These eruptions are violent and explosive
18
Q
What happens when two continental plates meet at a destructive margin?
A
- Both plates collide
- this makes the crust crumpled and uplifted
- This forms fold mountains and earthquakes
e. g himilayas
19
Q
Why is there no volcanoes at a destructive plate margin where 2 continatal plates meet?
A
-theres no magma
20
Q
What happens at a conservative plate margin?
A
- Two plates move past eachother in the same direction
- One plate is moving faster than the other
- This causes an earthquake due to the friction build up over many years
- the earthquakes are released suddenly when the plates slips and shifts
21
Q
What was the magnitude of the Chile earthquake?
A
8.8 on the richter scale
22
Q
What plate margin did the Chile earthquake take place at?
A
Destructive plate margin
23
Q
Where did the CHile Earthquake happen?
A
Out at sea creates waves of 800km/hour
24
Q
What was the magnitude of the Nepal earthquake?
A
7.9 on the richter scale
25
What plate margin did the Nepal earthquake take place at?
destructive plate margin
26
Where did the Nepal earthquake take place?
15km below the surface causing severe ground shaking and avalanches.
-
27
What is a Primary effect of an earthquake?
Something directly caused by the ground shaking, e.g. damage to roads and buildings, death and injuries
28
What is Secondary effect of an earthquake?
-A result of the primary effects , so ground shaking causing tsunamis, land slides and avalanches
29
What were the primary effects of the Chile Earthquake?
- 500 dead
- 12k injured
- 800k affected
- 220k homes destroyed
- Estimated cost of 30bn USD
30
What were the secondary effects of the Chile earthquake?
- 1500km of roads damaged
| - Fires at chemical plants, area had to be evacuated
31
What were the primary effects of the Nepal earthquake?
- 9000 dead
- 20k injured
- 8 million affected
- 1.4 million needed food and shelter
- Estimated cost of 5bn usd
32
What were the secondary effects of the Nepal earthquake?
- Ground shaking caused avalanches and landslides, blocking the roads
- Avalanches killed 19 people
- 250 missing due to avalanche
33
What is a Immediate response?
-Search and rescue and keeping survivors alive by provide medical care, food, water and shelter
34
What is a Long-term response?
-Re-building and reconstruction, with the aim of returning peoples lives back to normal and reducing future risk.
35
What were Chiles immediate responses?
- Repairs made to the North-South highway within 24 hours
| - Raised 60 usd milliion for 30,000 shelters
36
What were chile's long term responses to the Earthquake?
- Government launched reconstruction plan helping 200,000 homes
- re built their economy single handedly by increasing copper exports
37
What were Nepals immediate responses to the earthquake?
- Sent out search and rescue teams
- water, medical support and food arrived quickly from other countires
- 500k tents provided
- Field hospitals were set up
38
What were Nepals long term response to the earthquake?
- Roads were repaired
- landslides were cleared
- 7000 schools rebuilt
- Stricter controls on building codes
- They seeked technical and financial support for reconstruction from other countries
39
Why do people choose to live in tectonically active areas?
- Natural hazards do not happen often
- Building designs can withstand natural hazards
- There is now more effective monitoring of natural hazards
- Volcanoes bring fertile soil, rocks for building and rich mineral deposits
- People in poverty cannot afford to move and need to earn money which is more important to them
40
Whats it like living on a plate margin? (iceland)
- eruptions every 5 years
- people see the active volcanoes not as a great risk as there is very effective monitoring and awareness of potential dangers
41
What are the benefits of living on a plate margin? (iceland)
- Hot water from the earths crust provides heat and hot water for 90% of the buildings
- Volcanic rock is used for buildings
- Dramatic landscapes with waterfalls and volcanoes are great tourist attractions bringing 1 million tourists to the country each year
42
How can risks from tectonic hazards be reduced?
- Monitoring
- Prediction
- Protection
- Planning
43
What is monitoring, that is used to reduce tectonic hazards?
- Identifying to warning signs of magma rising through the volcano
- If an eruption seems likely warnings can be given and action can be taken by evacuating the surrounding areas
44
What are the different ways of monitoring a volcano?
Remote sensing- detects heat and changes to shape of volcano
Ground deformation- detects changes to the shape of the volcano by using laser beams
Geophysical measurements- Detects changes in gravity as magma rises
45
What is prediction? (natural Hazards)
- Use of historical evidence and monitoring to predict where and when a tectonic hazard is likely
- Predictions of a volcanic eruption is based on scientific monitoring. This was successful in Iceland 2010
- For an Earthquake it is impossible to make predictions due to the lack of clear warning signs
46
What is protection? (natural hazards)
-the designing of buildings which can with stand tectonic hazards
volcano
-e.g. Earth embankments made to direct lava away from property
Earthquake
-Using supported steel frames dug into to the ground to support the building, reducing the risk of tectonic hazards, this was done in Chile
47
What is planning? (natural hazards)
-volcano
Restricting certain land uses or identify areas which need to be evacuated prior to an eruption
-Earthquakes
maps produced to show areas most at risk of damage, as a result high value buildings and places can be protected e.g. hospitals and office blocks
48
How does global atmospheric circulation work?
-A number of circular air movements called cells join together to form the earths circulation
49
What happens when air sinks towards the ground?
-Forms areas of high pressure, winds move outwards from those areas e.g. North Pole
50
What happens when air rises from the ground?
Forms areas of low pressure on the ground, winds move towards it
51
Why are surface winds important?
-Because they move heat and moisture from one place to another
52
How are patterns of pressure formed and how are they affected?
-By the tilt and rotation of the Earth, changes position of sun
53
What are the 3 types of weather cells?
- Hadley
- Ferrel
- Polar cell
54
Why is it cloudy and wet in the UK?
- In boundary of cold polar air moving down, and sub tropical air moving up
- There are Rising air and low-pressure belts, meaning rising air cools condenses and forms clouds
55
What are the cells of the earths atmosphere?
- Polar high, sub polar low
- Subtropical high
- Equatorial low
56
What is a tropical storm?
A huge storm which develops in the tropics
57
Where do tropical storms form?
- Over seas above 27 degrees
- When sea temperatures are highest
- 5-15 above equator for the coriolous effect
- In intense heat to make the air unstable, allowing it to rise
58
How do tropical storms form?
- Upward movement of air draws water vapour up from sea surface
- Cools and condenses into towering clouds
- As air condenses heat is released to power the storm and draw up more water
- Small thunderstorms join together, reaching over 120km making it a tropical storm
- Storm eye develops, air descends rapidly
- As storm travels over ocean, it gathers strength
- When storm reaches land, evaporated water source is cut off, storm creates friction with the ground and slows down and weakens.
59
Where do the most intense weather conditions of a tropical storm happen?
-Outer edge of the storm eye, the eyewall
60
What has happened to sea surface temperatures over the past few years?
Risen from 0.25-0.5 degrees
61
What are the effects of Climate Change on Tropical storms?
- Distrubution may become wider
| - Areas outside of the hazard zone might be affected
62
What was the impact of hurricane Katrina?
-40k homes damaged
63
Why was Hurricane Katrina a surprise?
- The South Atlantic oceans are ussaully below the minimum temperature for hurricane formation
- Sea surface temperatures were unsually high
64
What may happen to the frequency of tropical storms in the future?
-It may decrease, but the intensity of them might increase
65
How has the intensity of tropical storms changed over time and why?
-North Atlantic has risen of over the last 20 years due to rise in sea surface temperatures
66
When was Typhoon Haiyan?
November 2013
67
What category storm was typhoon Haiyan?
5
68
What were the effects of typhoon Haiyan?
Primary- 6.3k killed
- 40,000 houses destroyed
- Widespread flooding
Secondary- 14m affected
- Power supplies in some areas cut off for a month
- shortages of food and water leading to famine and disease outbreaks.
69
What were the response to Typhoon Haiyan?
- Short term: -International food, water and shelter aid sent
- 1.2k evacuation centres set up
- International field hospitals set up
Long Term;- rebuilding of roads, bridges and airports
- Homes built away from flooding
- Cyclone shelters built for people on the coasts
70
What is urbanisation?
-proportion of worlds population living in cities grows, due to increase of population and migration
71
How does urbanisation vary around the World?
- In LIC's 60% of population live cities
- South Asia, half of populations live in towns and cities
- In Africa almost all nations have above 20% of population living in cities
72
What is projected to happen to the Worlds Urban growth in the next 30 years?
- Largest growth to be in India and Nigeria
- 3 countries will be accountable for 37% of the Worlds Urban population
- India project to add 404 million urban dwellers by 2050
73
Why do cities grow?
Rural to Urban migration, due to push and pull factors
-Natural increase, birth rate will be higher than death rate, with less older people the death rate is lower and there will be improvement to health care at the same time factors
74
What is a push factor?
A reason to leave an area
75
What is a pull factor?
A reason to leave an area
76
What is a mega city?
- A city with a population of above 10 million
77
Where are some slow growing cities and what are their features?
- Moscow and Tokyo
- Population lives in urban areas, 70% +
- No squatter settlements
78
Where are some growing cities and what are their features?
- Rio and Beijing
- Population 40-50% live in urban areas
- Under 20% of population in squatter settlements
79
What is Rio De Janeiro like?
- City of extremes
- Homes Brazils largest favela, Rochina
- areas of afluence and areas of poverty
- Densely populated
- Beautiful landscapes and beaches attracts many tourists
80
What does Rio De Janeiro entail?
- Major World export of Coffee sugar and iron ore
- Creates 5% of the nations GDP
- Most buissnes' are in the teritiary and quaternary sectors
81
What are some of the land uses in Rio De Janeiro?
- North Zone- City's main industrial area
- City's main International airport
West Zone- Area of luxury with Malls, luxury apartments and tourist facilities
-Olympic Village
Central- Oldest part of the city
- City's main shopping area
- Financial headquarters of Brazils largest oil and mining companies
South- Wealthy area overlooked by Rochina
82
What are the social challenges in Rio de Janeiro?
health care
education
water supply
energy
83
Expand on Rio de Janeiro's Health issues and the solutions>
- 55% of city had access to local health clinics (2013)
- Services for pregnant women were poor, only 60% of women in city of God got medical care when giving birth
- Some areas in the city have a life expectancy of 45
Solutions
- Medical staff went to homes and treated 23 types of diseases in Santa Marta favela
- Cleared roads and widened them to make the hospital more accessible
84
Expand on Rios' education issues and what are the solutions?
- School is compulsory between 6-14, many drop about, some get involved in drug trafficking
- Shortage of schools
- Shortage of teachers
- Lack of money invested
Solutions- Locals encouraged to help in schools
- Free to play sessions opened to the public
- Rochina will open a private university
85
What are the water supply issues in Rio and what are the solutions?
37% of water is lost through leaky pipes, fraud and illegal access
solutions- 300km of pipes had been relaid over 16 years
-95% of homes have access to mains water supply
86
What has economic development brought to Rio De Janeiro?
Improved roads, transport, services and enviroment
| -also a range of new economic oppourtinites in the formal industry
87
What percentage of employment does Rio hold for Brazil?
Above 6%
88
What are the types of employment in Rio?
- Oil refining
- Port industires
- manufacturing
- Tourism
- Construction
89
Why has unemployment increased in Rio?
-Protest against the high taxes, poor education and inadequate health care
90
What is work like for people who live in the favelas?
- Less than £60 per month
- In the informal economy on the most part
- 1/3 of Rios workers do not have a formal working contract, so they pay no tax and the government recieves no income off them
91
What is the crime problem in Rio? and what have the police done?
- Drug trafficking, robbery, kidnapping etc. is a daily occurance
- The police have taken over 30 drug dominated favelas, they aim to reduce crime rates, to increase tourism to improve lives in the favelas
92
What are Rio's environmental challenges?
Air pollution
traffic congestion
water pollution
93
what are the effects of the air pollution and traffic congestion in Rio and what are the solutions?
- Air pollution causes 5,000 deaths per year
- The city is covered in brown smog due to the pollution from cars
- Number of cars in Rio has grown by 40% in the last 10 years
Solutions: -Expansion of metro systems
-New toll roads made to reduce congestion and encourgae metro use
94
What affects does water pollution have on Rio's environment and what are the solutions?
- Bays are highly polluted, threatening wildlife
- worries of pollution affecting tourist beaches, lowering tourist rates
- 20000kg of sewage pours into the bay each day
- many oil spills from oil refinery
solutions; - 68 million usd spent on new sewage works
-5km of new sewage pipes put in
95
Briefly, what is the Rio-bairro project?
- A project implemented to improve the favelas with 1 billion usd
96
How does the long profile of a river change downstream?
- In the mountains- water is shallow and turbulent due to friction with the river beds, slowing down the flow
- Further Downstream- River channel is deeper due to tributaries brining more water. Velocity increases as less water is in contact with the river bed. Less steep gradient
97
What is the gradient like in the upper course of the river?
-Steep
98
What is the gradient like in the Middle course of the river?
- gentle
99
What is the gradient like in the lower course of the river?
-very gentle
100
What are the river and valley like in the upper course?
| Cross profile
RIVER - narrow, shallow turbulent
Valley- Steep sided, V shaped
101
What are the river and valley like in the middle course?
| cross profile
RIVER- Wider and deeper
Valley- Wider, Flat floor
102
What are the river and valley like in the lower course?
| cross profile
River- Wide, deep, large sediment load
Valley- very wide and flat
103
Why does the cross profile of a river and its valley change downstream?
changes downstream are due to the amount of water and channel erosion, the drainage basin becomes bigger bringing more energy allowing it to erode the channel making it wider and deeper.
104
How does weathering affect the cross profile?
- They types of weathering cause channel erosion, broadening and flattening the base of the valley. These make the sides of the valley less steep
105
What are the two types of erosion?
- Vertical and Lateral
