SectionA:Challenge of natural hazards Flashcards
global atmospheric circulation
an aeroplane travels at an altitude of around 10km above the ground surface. Below this the vast majority of the atmospheres mass is below you. The atmosphere- the air above our heads- is a highly complex
How to remember conditions in high pressure
Happy- settled weather
High pressure
Cool air descends, reduces cloud formation, light wind and settled weather
Air moves clockwise
How to remember low pressure weather conditions
Lashing down
Low pressure
Hot air rises, evaporation and condensation to form clouds, rains
Air moves anti-clockwise
Unsettled weather-rain
Polar cell occurs between…
60 and 90 degrees
What happens to the trade winds at areas of high pressure
Move away
A ferrel cell occurs between…
30 and 60
A Hadley cell occurs between…
0 and 30 are
What do trade winds do at areas of low pressure
Move towards
Three names for tropical storms
Cyclones, typhoons, hurricanes
What countries would be affected by a cyclone
India, Madagascar, Australia
What countries would be affected by a typhoon
Japan, south-east Asia, Philippines
What countries would be affected by hurricanes
Caribbean, USA
Where do hurricanes get their energy from
Warm seas
Temperature of the ocean for hurricanes to form
27+
What degrees north of the equator do hurricanes form
8 and 20
What ocean do hurricanes form in
Centre of the Atlantic
What oceans do typhoons occur in
West of the Pacific
What oceans are cyclones formed in
South west Pacific and Indian
What happens in the eye of a hurricane
A small area where cooler air sings towards the ground and warms up, no clouds here and conditions are calm
Eye wall conditions
Tall bank of clouds where there are strong winds, heavy rain, thunder and lightening
How do hurricanes form
Strong upward movement of air draws water vapour up from the sea
Air condenses and releases heat which powers the storm and draws up more air from the ocean
The storm develops an eye where air descends rapidly
The evaporated air cools as it rises and condensed to for cumulonimbus clouds
Several small thunderstorms join together, when the winds reach 75mph the storm becomes a tropical storm
As the storm is carried across the ocean by prevailing winds it continues to gather strength. On reaching land the storms energy supply is cut off
What speed to the winds have to reach to become a tropical storm
75 mph
When was hurricane Katrina
August 2005
About the hurricane
Category 5 175 mph wind speed 400 miles wide SE of Louisiana Formed in Atlantic
3 primary and secondary effects
P: 30 oil platforms destroyed-S: millions of oil leaked due to spills
P:water and gas pipes snapped-S:80% of the city flooded, stayed for weeks
P: over 1800 deaths
S:100,000 left without power
Immediate responses
People tried to swim to safety
300,000 couldnt/ wouldn’t leave
Super dôme accommodated 20,000
Long term responses
Levees were replaced/ strengthened
Buildings repaired
Monitoring and predicting tropical storms
Using scientific equipment to detect warning signs and predict when the hurricane will occur
Advantages and disadvantages of monitoring and prediction tropical storms
A- warning to evacuate A- technology is more accurate A- death decrease D- not always accurate D- people may not leave D- future track is uncertain
Protection
Designing buildings that will withstand a hurricane
Protection advantages and disadvantages for tropical storms
A- reduce flood effects A- people feel safer A- reduce deaths D- expensive D- people may have to travel far D- buildings may not accommodate enough people
Example of monitoring and predicting tropical storms
Hurricane watch
Hurricane warning
Example of protection hurricanes
Reinforce windows, doors and roofs
Storm drains to prevent floods
Houses built on stilts
Planning tropical storms
Identifying and avoiding places most at risk
Planning advantages and disadvantages tropical storm
A- people know how to respond A- deaths decreased A- own responsibility D- people may not leave D- storm path may change D- messengers may be too late
Example of planning tropical storm
Bangladesh have early warning systems by educating locals on storms
Cyclones tracked and warnings issued by radio and social media
People in rural areas can be reached by bike- may be too late
Weather
Weather is the atmospheric conditions over a short period of time
Eg today it is cold
Climate
The average weather conditions over a long period of time 30-50 years
Eg the arctic has a cold climate
Why does extreme weather occur in the UK
Attic winds- heavy snow, bitter cold
America’s winds- storms being heavy rain and strong winds from remains of hurricanes
Mediterranean- hot and sunny, heatwaves and droughts
Russia- severe winter weather comes from the east
Examples of weather hazards
Thunderstorm
Strong winds
Drought
Prolonged rainfall
Thunderstorm cause
Hurricane remains from Caribbean
Drought cause
Period of high temperatures and little/ no rainfall
Heavy snow
Freezing temperature lead to snow and ice covers, lower visibility makes roads dangerous
Prolonged rainfall
Rainfall over a long period of time can lead to river flood this is common when snow melts
Weather hazard case study
Somerset 2014 floods
Where is Somerset
South east of the uk
Causes of Somerset
350mm of rain fell in January and February, 100 Mm above average
High tides, storm surges prevented water from rivers reaching the sea
Rivers hadn’t been dredged in 20 years
Primary and secondary effects of Somerset
600 homes flooded-> residents lived in temporary homes for several months
Local roads cut off-> people couldn’t get to work or school
S: damage estimated £10 million
Immediate responses of Somerset
Block doors with sandbags
Evacuate
Locals used boats to get to school
Long term response of Somerset
Dredging
How to describe the trend of an average temperature graph
General trend
Manipulate data
What could more energy in the atmosphere lead to
More intense storms
Atmospheric circulation affected so floods could be brought to dry regions and heatwaves to cool areas
Glacial period
When ice sheets have covered extensive parts of the earth
Interglacial
Warmer period such as the current era where not as much ice covers the earth
Three physical causes of climate change
Orbital changes, solar activity, volcanic activity
Orbital changes
Axial tilt- earth spins on it’s axis causing night and day. The angle can change between 21.5 and 24.5
Precession- natural wobble can take 26,000 years
Eccenticity cycle- as the earth orbits the sun can change from circular to elliptical
Solar activity
Sunspot is a dark patch on the surface of the sun
When at maximum more heat given off
When at minimum less heat given off
Can change from min to max in 11 years
Volcanic activity
Violent éruptions blast huge quantities of ash and gas into the atmosphere
Volcanic ash can block the sun which reduces the earths temperatures
Human causes of climate change
Increase in
CO2
Methane
Nitrous oxide
CO2
Deforestation
Burning fossil fuels
Car exhausts
Methane
Rice farming
Livestock
Decaying organic matter
Nitrous oxide
Sewage treatment
Car exhausts
Power stations producing electricity
Climate change evidence birds
Bird migration is changing
65 species of birds are nesting on average 9 days earlier in the mid 1990s than in 1970s
Climate change evidence glaciers
Glaciers are shrinking and retreating
Estimated some will completely disappear by 2035
Climate change evidence sea level
Global sea level has risen 15 cm in the last 100 years. This is because
When temperatures rise and fresh water melts more water flows to the seas from glaciers
When ocean water warm it expands in volume- thermal expansion
What is mitigation
Reducing the severity and seriousness of climate change
Mitigation strategies
Alternative energy sources, planting trees, international agreements
Alternative energy sources facts
Hydroelectric/ nuclear/ solar
Reduce CO2 émissions
UK aim- 15% of energy from renewable sources by 2020
What is a carbon sink
Natural environment viewed in terms of its ability to absorb CO2 from the atmosphere
Planting trees facts
Trees act as carbon sinks removing CO2 from the atmosphere by photosynthesis. Trees also release moisture into the atmosphere
International agreement facts
2005- Kyoto protocol. 170 countries agreed to reduce emission by 5.3%
2015- Paris agreement. 195 countries keep global temp increase below 2 degrees
Adaptation
Make changes to prepare for the effects
Types of adaptation
Managing water supply, reducing risk from sea level rise
Managing water supply facts
Planting shade trees to protect seedlings from the sun
Drought resistant crops eg maize
Educating farmers
Reducing risk from sea level rise facts
Relocating populations
Sea wall construction
Why do sea levels need to be managed
As by 2100 sea levels are expected to rise by a further 26-82 cm
Monitoring tectonics
Using scientific equipment to detect warning signs
Volcano monitoring
Remote sensing- satellites detect heat and changes to shape
Seismicity- records earthquakes
Gas- instruments detect changes in gas
VERDICT: many ways, successful
Earthquakes monitoring
Generally occur without wanting
Minor tremors prior, slight changes in water pressure
VERDICT: havent discovered ways to monitor earthquakes yet
Prediction tectonics
Using historical evidence to make predictions
Prediction volcano
Historical evidence
Monitoring to detect changes
Verdict: used with monitoring, without monitoring prediction would be so hard
Earthquakes prediction
Lack of warning signs
Historical records at plate margins identify places at greater risks
Verdict: impossible to predict, hard to evacuate
Protection tectonics
Designing buildings that will withstand tectonics
Volcano protection
Earth embankment to form a barrier
Explosives divert lava away from properties
Verdict: only works with thin runny lava
Earthquakes protection
Construct buildings and bridges to resist ground shaking
Reinforced with steel to reduce movement
Verdict: earthquakes don’t kill, buildings do
Planning tectonics
Identifying and avoiding places most at risk
Planning volcanoes
Hazard maps designed for areas most affected
Certain areas can avoid being built on
Verdict: nobody in affected area isn’t a hazard but people then can’t benefit from the volcano
Earthquake planning
Maps produced, high value land can be protected
Verdict: earthquake can occur at different locations so hard to plan
Natural hazard
A natural event that has an impact on people and human activities
Atmospheric hazards
Cyclone, forest fire, lightening, thunderstorm, hurricane, hailstone, drought, tornado
Geological hazard
Volcanic eruption, landslide, avalanche, tsunami, earthquake
Flooding hazard
Flood
Types of natural hazard
Atmospheric, geological, flooding
Hazard risk
Likelihood of being affected by a natural event or
What factors can affect risk
Urbanisation, poverty, climate change, farming
Urbanisation risk
Growth of towns and cities
Increase hazards as more people would be affected. 50% of worlds population lives in cities, buildings close together, can cause domino effect
Poverty risk
Extremely poor
- May force people to live in areas of high risk, houses less stable and collapse easier. People get trapped, not enough healthcare so people die
Climate change risk
Change in the worlds weather pattern
- when the weather is warmer the atmosphere has more energy so there are more extreme storms
Farming risk
When a river floods it deposits silt and makes land fertile meaning crops grow better however there is a risk of flooding if you live there
Human developments that would increase risk of people being affected by natural hazards
Urbanisation, poverty, farming
Environmental developments that would increase risk of people being affected by natural hazards
Climate change, farming
Earthquake
Sudden and short period of intense ground shaking the
How to describe the distribution of earthquakes
Clustered/ linear/ scattered
Then compass points
What is distribution
The way something is spread over an area
Segments of the earths crust
Tectonic plates
How many km thick is continental crust
25-90
Type of rock is continental crust made from
Granite
How many km thick is oceanic
6
Type of rock is oceanic made from
Basalt
What moves the plates
Convection currents in the mantle in
Three directions the plates move
Apart, towards, slide past
What features can occur due to the movement of plates
Mountain ranges
Earthquakes
Volcanoes
Island
Hawaii is an example of what
A hotspot
How far have the plates moved apart since 1492
25 m
Characteristics of oceanic
Denser
Thinner
Renewed and destroyed
Characteristics of continental
Older
Thicker
Less dense
What are convection currents
Created by heat from the core
Hot magma rises then cools and sinks and drags the plates- separating them
Type of crust destructive
Oceanic and continental
Type of crust constructive
Oceanic and oceanic
Direction of movement constructive
Apart
Structure created constructive
Shield volcanoes
Example constructive
North America and Eurasian
Types of plate boundaries
Constructive, destructive, conservative
Movement destructive
Together
Features created destructive
Earthquakes composite volcanoes mountains tsunamis
Example destructive
Nazca and South American
Key word destructive
Subduction zone/ subducted
Conservative crust
Any
Conservative direction
Sliding past
Features conservative
Earthquakes
Example conservative
Pacific and North American
HIC earthquake study
Chile
When did chile occur
2010
Duration chile
3 mins
Plate boundary chile
Destructive
4 primary effects chile
500 deaths
56 hospitals collapsed
220,000 homes destroyed
Cost US $30 billion
Three secondary effects
No healthcare
Lost power water and communication
Homelessness
Immediate responses
Power and water restored to 90% in 10 days
Temporary repairs made to highways within 24 hours
Long term responses
A month after the government launched a housing reconstruction to help house holds affected
President will take 4 years to recover damage
What caused the chile earthquake
Nazca subducted under SA plate
Environmental effects of chile
Pollution
Habitats
Floods
Social effects of chile
Education Housing Transport Health Clean water Sanitation
Economic effects chile
Employment
Taxes
Income
Business/industry
Nepal Richter scale
7.8
Nepal date
2015
Duration chile
50 seconds
Plate boundary Nepal
Destructive
Nepal plate boundary
Indo Australian and Eurasian
Primary effects Nepal
Over 9000 killed
50% shops destroyed
Cost $5 billion
Secondary effects Nepal
Avalanches killed 19
1.4 million needed food, water and shelter
Landslide blocked Gandaki river
Immediate response nepal
Helicopters rescued many people from avalanches
Half a million tents needed to provide shelter
Search and rescue quickly arrived from UK India and China
Long term responses Nepal
Repairs to Mount Everest 4 months later
International conference held to discuss reconstruction and seek support from other countries
Economic factors affecting risk
People living in poverty have other things to worry about
Housing is cheaper in some of these areas
Tectonic features can attract tourists which would be a good source of income for people living in poverty
Social factors affecting risks
People living in poverty have other things to worry about
Some people may not be aware of the risks of living close to a plate margin
Better building design can withstand earthquakes so people feel less at risk
Earthquake and volcanic eruptions do not happen very often they aren’t seen as a great threat in people lives
Environmental factors living with the risk
volcanoes bring benefits such as fertile souls rocks for building and hot water
Fault line associated with earthquakes can allow water supplies to reach the surface
Plate margins are often in favourable areas for settlements such as coastal areas
