Global Hazards Flashcards
What is the difference between a hazard and a disaster?
Hazards are possible dangers which could happen but a disaster is something that has actually happened
What is the difference between weather and climate?
Weather is day to day conditions of the atmosphere e.g. wind, rain, sun
Climate is the average conditions of a place e.g. temperature and rainfall
How does the Earth evenly distribute energy from the sun
Most of the energy enters the earth through the equator, this causes the air to heat up and rise. It then moves along the earth’s surface and cools down and heats up, this distributes the energy around the globe.
What is the climate like at the equator where the Hadley cells meet
Hot, low pressure and lots of clouds
What is the climate like where the Hadley cell meets the Ferrel cells
Quite hot, high pressure, very few clouds, cold at night
What is the temperature like where the Ferrel and Polar cells meet (The UK)
Low pressure, clouds and quite cold
What is the conditions like at the poles
High pressure, few clouds, cold
Why are the polar regions not warmed as much by the Sun as the Equator
Because the energy has to travel further through the atmosphere and there is more area being heated.
What is the Albedo effect
This is how much a surface reflects or absorbs the Sun’s rays.
e.g. polar ice has a high Albedo effect and reflects the heat. This makes the poles colder. Rain forests and oceans have low Albedo effects and absorb lots of heat
What is Cloud cover
Clouds reflect heat and at places where there are lots of clouds, the temperature is lower
What effects does the wind have
Surface winds move heat around the world
What are Ocean currents
Because water is fluid, ocean currents move heat easily
e.g. The UK is warmer than other countries on its latitude because it is warmed by the North Atlantic Drift.
It is a warmer current which originates in the Caribbean
What is the effect of Land and sea
On land, insulation is concentrated on the surface.
But at sea it reaches deeper because water is transparent
Water is slower to warm up but it stays warmer for longer
What is the effect of Altitude
Higher up, air pressure is lower, which makes temperature colder. They drop by about 1 degree every 100 metres in altitude
What causes wind?
Movement of air from places of high pressure to places of low pressure
Why does Antarctica frequently experience strong winds?
Because the large ice sheets which gently slope into the sea contribute to the wind speeds, Katabatic winds
Why does the change in relief lead to heavy rain?
Because the mountains cause the clouds up higher into the air which causes them to condense and collect a lot of water. This means that the clouds are heavy and it rains very hard.
What hazards could such heavy rainfall bring to this area of steep relief?
Flooding
Where do tropical storms form?
Over tropical oceans
What is a drought?
They are periods of time where there is much less precipitation in an area that is predicted
What is El Nino
El Nino events are related to weaker trade winds and lead to warmer than usual sea surface temperatures in the Pacific Ocean. They can cause drought in such areas as Australia and Asia.
What is La Nina
La Nina events are related to stronger trade winds and lead to cooler than usual sea surface temperatures in the Pacific Ocean. They can cause drought in such areas as California and Peru.
What are the causes of Typhoon Haiyan
- Really warm water (30 degrees) in the pacific ocean off the coast of micronesia
- Very little wind to destroy the storm, Thunderstorms developed and clustered together
- 7 degrees north of equator so coriolis effect can take place - Thunderstorms begin to rotate around each other
- Lack of wind shear allows the storms to develop into a typhoon
- Slowly moves west toward Philippines gaining energy from warm sea
What were the primary consequences of the Typhoon
5000 deaths
Houses, buildings, infrastructure destroyed by wind
Heavy rain lead to flash floods and landslides
People were drowned and killed or injured by falling debris
What were the secondary consequences of the Typhoon
Tsunami scale storm surge swept away buildings
Essential help was slow in remote places
People were left with no shelter, clean water or electricity
Roads were blocked by trees and 453 flights were cancelled
People were devastated by loss of family members
What were the Emergency responses to the Typhoon
RAF delivers 200 tonnes of aid - Medicine, Food, Water
Hospital tent set up
UN appealed 190 million for emergency aid
What were the long-term responses to the Typhoon
Clearing debris and managing waste
Repairing infrastructure
Replanting mangroves around the coasts
What were the causes of the drought in the UK
- Less rain - The area affected by drought received only 55-95% of usual rainfall between April 2010 and May 2012. Unusual wind patterns brought dry winds instead of wet winds.
- Warmer temperatures - The weather was warmer than usual, so more water evaporated from reservoirs than usual and soils dried out
- Dry soils - It was difficult for the rain that did fall to soak into the ground as the soil was dry and baked hard
- High water usage - People in the UK are in the habit of using large amounts of water in their everyday lives. Massive amounts are also used in industry and farming. This leads to around 1.7 billion litres of water being used everyday. Water is also wasted through leaking pipes.
What were the social consequences of the drought in the UK
20 million people weren’t allowed to use hose pipes to water their gardens or wash their cars
What were the economic consequences of the drought in the UK
Less farming as water was limited for crops and livestock
What were the environmental consequences of the drought in the UK
Reservoirs are nearly empty
Dry areas of moorland caught fire easily - wildfire
Reduced river levels
Damage to plants and animals
What was the response to the drought in the UK
- Restrictions on water use
- Permits were granted to allow the water companies to extract water from rivers
- They issued hosepipe bans to conserve the water that was available
- There were campaigns to get ordinary people to use less water in their homes
What happens at a destructive plate boundary
The oceanic crust goes beneath the continental crust because it is heavier
What happens at a constructive plate boundary
The plates are moving apart from each other which means that land is created
What happens at a collision plate boundary
The two continental plates move into each other
What happens at a conservative plate boundary
The two plates move alongside each other
How do plates move?
Convection currents in the mantle
Ridge push - new crust rises because it is warm and thin, creating a ridge. It pushes older crust away from the ridge
Slab pull - old crust is cooler and thicker than the hot mantle, so it sinks into the mantle
What is formed at destructive boundaries
Earthquakes and volcanoes
e.g. Andes
What is formed at collision boundaries
Volcanoes
e.g. Himalayas
What is formed at constructive boundaries
Volcanoes and earthquakes
e.g. mid-Atlantic ridge
What is formed at conservative boundaries
Earthquakes
e.g. San Andreas Fault
What is the richter scale
The richter scale measures the magnitude which is the amount of energy released. This is a logarithmic scale so a magnitude of 7.0 is ten times more powerful than a magnitude of 6.0
what is the mercalli scale
The mercalli scale measures the damage and effects of the earthquake. It goes from 1 to 12, with 12 being the biggest
What are seismometers
Seismometers are used to record the earthquake, this data can be combined with other information to produce a geographical information systems
What is a shield volcano
Form on constructive boundaries Runny lava Shaped like a shield they happen at hotspots where the crust is thin and there is a blume of magma Gentle eruptions
What is a composite volcano
Form on destructive boundaries
Thick lava
Steep slopes
Eruptions are very powerful and release steam and dangerous gases
What are the causes of the Haiti earthquake
Caribbean plate moves eastwards towards the North American plate
Haiti is located on the caribbean plate at a conservative plate boundary
Friction and pressure built up at a parallel faultline 100km south of the main boundary
Pressure was released in a shallow focus earthquake in Port-au-Prince, Magnitude 7
what were the primary effects of the earthquake
Damage to the port - liquefaction meant that it was out of action and was unable to receive aid shipments
Damage to buildings - UN HQ + Presidential Palace
Response to disaster slowed down by damage to the Palace and HQ
1.5 million people displaced by it
What were the secondary effects of the earthquake
Looting and Rioting
UN peacekeepers from Nepal brought cholera with them + contaminated the Artibonite river. The disease spread rapidly in camps
What were the Immediate responses to the earthquake
US air force took over air traffic control to ensure aid could be flown in - Food, medicine, shelter, clothes, water purification
Air drop deliveries of aid - 350 Million promised by the EU for short term relief and long term recovery.
Set up IDP camps (internally displaced people)
UN peacekeepers sent into establish law + order
Ushahidi - Users reported incidents using mobile phones + this was mapped using open mapping software. NGOs could access this data + quickly respond to incidents
What were the long term responses to the earthquake
Health costs 34.3 million dollars to rebuild
Education costs 23.1 million dollars to rebuild
Prediction of earthquakes
We can not predict time, location, magnitude or data
We can forecast possible earthquakes + their locations
This is important as it allows for preparation
Possible theories - Animals behaviour and Radon gas
But these are not very reliable
Protection from earthquakes
Base Isolation - Foundations absorb the shaking and protect the building above
Tuned Mass Damper - Big Ball in roof of skyscrapers which act as a counterweight to buildings sway
Reinforced Concrete - Using steel to support concrete structures.
Preparation for earthquakes
Practice Drills
Youtube Videos
Rations, securing the home, Emergency bag
