Natural Hazards Flashcards
Define ‘natural hazard’
A natural event (for example earthquake, volcanic eruption, tropical storm, flood) that threatens people or has the potential to cause damage, destruction and death.”
What are the two main categories of natural hazard, give some examples of each
Atmospheric/ Meteorological (to do with the weather): Tropical storm, heatwave, blizzard, heavy rain
Geological (to do with the surface of the earth): volcano, earthquake, landslide
List 3 factors that affect the risk of hazards?
Urbanisation: densely populated urban areas will have a greater risk from hazards. Wealth: poor countries will be less able to prepare for, and respond to hazards Frequency: places that have multiple hazards, or frequently experience hazards will deal with them differently.
What is plate tectonics theory?
A theory that explains how the Earth is structured and what it is made up of.
Describe the distribution of earthquakes and volcanoes
Earthquakes and volcanoes are primarily found along plate margins for example the edge of the Pacific Ocean (the “Ring of Fire) and in the middle of the Atlantic Ocean. There are however some that are found in the middle of tectonic plates
List 4 primary effects of Tyhoon Haiyan
- 6,300 people were killed, mostly drowned by the storm surge
- 600,000 were displaced
- 40,000 homes were destroyed
- Strong winds damaged buildings and power lines and destroyed crops
List 4 secondary effects of Typhoon Haiyan
- 14 million people were left homeless and 6 million lost their source of income (mainly fishing)
- There was looting and violence in Tacloban
- There was a shortage of food, and rice prices increased by 12%
- Power supplies in some areas were down for 1 month
List 4 immediate responses to Typhoon Haiyan
- 800,000 people were evacuated by the Government
- 1200 evacuation centres were set up
- 1 million food packs and 250,000 litres of water were sent by charities such as the Philippines Red Cross
- The UK Government send shelter kits, each one providing emergency shelter for one family
List 4 long term responses to Tyhpoon Haiyan
- Rebuilding of raods, bridges and airport facilities
- Charities such as Oxfam helped replace fishing boats, which are a vital source of income
- Thousands of homes rebuilt away from areas at risk of flooding
- More shelters built to accomodate people evacuated from coastal areas
What happened during Typhoon Haiyan?
Typhoon Haiyan was a category 5 Tyhpoon (tropical storm). There were winds of up to 275 km/hour and waves as high as 15m.
When was Typhoon Haiyan?
Typhoon Haiyan happened on 8th November 2013
List 4 ways in which we can protect against a tropical storm
Reinforce windows, doors and roofs to withstand strong winds
Houses close to the coast can be built on stilts so that a storm surge passes beneath them.
Storm drains built in urban areas to take away excessive amounts of rainfall and prevent flooding
Sea walls built to protect key properties from storm surges
List 2 ways a tropical storm can be monitored and predicted
- Satellites monitor the clouds for the classic cloud pattern associated with tropical storms
- Supercomputers such as those developed by the National Oceanic and Atmospherice Administration (NOAA) try to predict the path of tropical storms
List 4 ways in which we can plan to reduce the effects of tropical storms
1.
In the USA they have National Hurricane Preparedness Week so people can be educated on the possible dangers of tropical storms.
Try to limit the amount of building that is done on low lying or vulnerable areas
Make sure you are prepared personally: petrol in the car, food and supplies at home.
People can be supplied with disaster preparation kits
What type of weather hazard does the UK experience?
Heavy rain
Flooding
Heatwave
High winds (gales and storms)
Extreme cold (snow and ice)
What caused the Somerset Floods?
- Wettest January since 1920, 350mm of rain fell in January and February (100 mm above the average)
- The land in Somerset is very low-lying, with several rivers all flowing into the Severn estuary
- High tides and storm surges swept water up the rivers.
- Rivers hadn’t been dredged in at least 20 years meaning they were clogged with sediment
What were the social impacts of the Somerset Floods?
- 600 houses flooded
- 16 farms evacuated
- Many residents in temporary accomodation for several months.
- Villages such as Moorland and Muchelney cut off completely
What were the economic effects of the Somerset floods?
- Somerset Council estimated the cost of the flooding to be more than £10 million
- Over 14000 hectares of agricultural land underwater for 3 - 4 weeks (loss of income for farmers)
- Bristol to Taunton railway line was closed at Bridgwater
What were the environmental impacts of the Somerset floods?
- Floodwaters were heavily contaminated with sewage and other pollutants
- Huge amount of debris had to be cleared
- Stagnant water that had collected for months had to be treated before it could be pumpted back into rivers
What were the short term responses to the Somerset Floods?
- Villagers used boats to go shopping and get to scool
- Local community groups and volunteers provided support
- Neighbouring farms offered to take in animals that were stranded
What were the longer term responses to the Somerset Floods?
- £20 million Flood Action Plan to reduce the risk of future flooding
- 8km of rivers were dredged to increase the capacity of the River Channel
- Vulnerable locations will have flood defences built
- Road levels have been raised
State 3 bits of evidence for climate change?
- Ice cores - gases trapped in the ice can tell us what the temperature was like up to 400,000 years in the past.
- Shrinking glaciers - Arctic sea ice has thinned by 65% since 1975.
- Tree rings - the thickness of each ring shows us what the climate was like over the last 10,000 years
What are the 3 natural causes of climate change
- Orbital changes (Milankovitch Cycles): The Earth’s orbit around the sun changes in 3 ways: the tilt on it’s axis, the shape of the orbit, and the ‘wobble’ of it as it spins. This means we are either closer to, or further away from the sun.
- Sunspot theory: When the surface of the Earth has more ‘sunspot activity’, the temperature is warmer
- Volcanic eruptions: These put large amounts of gas and ash into the atmosphere blocking out the sun, and lowering the temperature
State 3 types of greenhouse gas, with an example of an activity that causes it
- Carbon Dioxide: burning fossil fuels for electricity, driving cars, deforestation, burning wood
- Methane: farming rice, decaying material in landfill, farming cows
- Nitrous oxide: Sewage treatment, car exhausts, agricultural fertilisers
List 3 social effects of climate change
- Approximately 70% of Asia may be at risk of flooding from sea level rise
- In Europe more heat waves can increase deaths
- Drought is likely to put pressue on food and water supplies in sub-Saharan Africa
Name the three cells in the tri-cellular model
Hadley cell
Ferrel cell
Polar cell
Which cell of air lies between the tropics and the Equator?
The Hadley Cell
Which cell is associated with bringing very cold winter weather?
The Polar Cell
What is a tropical storm?
A huge storm which develops in the tropics. The storms are powerful and are associated with strong winds and torrential rain.
Where do tropical storms form?
- over warm oceans (27 degrees C)
- 5-15 degress north and south of the equator
- Where intense heat makes the air unstable causing air to rise rapidly.
What temperature does the sea need to be for a tropical storm to form?
27 degrees
What are the three names for tropical storms and where are they located?
Cyclones - South east Asia and Australia
Typhoons - Japan and the Phillipines
Hurricanes - USA and Caribbean
When evaporated air rises it cools and condenses to form what?
Clouds
What is the name of the thunderstorm clouds associated with tropical storms?
cumulonimbus clouds
What happens at a constructive plate boundary?
- Convection currents in the mantle cause the oceanic plates to move apart from one another.
- Magma rises between the plates, hardens and cools to form new oceanic floor
- This causes earthquakes and shield volcanoes
What happens at a destructive plate margin?
A continental and oceanic plate are moving towards each other.
The oceanic plate subducts beneath the continental plate because it is denser and heavier.
This plates melts into the magma.
The continental plate is pushed upwards to form fold mountains and a composite volcano is formed
What happens at a conservative plate boundary?
- Convection currents in the mantle cause two tectonic plates to slide past each other.
- They might be going in different directions, or the same direction but at different speeds.
- This causes earthquakes, but not volcanoes
From the inside out, label the sections of the structure of the Eart
