Hazards Flashcards
(28 cards)
How does an ageing population increase risk from hazards?
They are the least mobile in communities.
Less capacity to take action.
Why are floods and windstorms increasing?
Increased warming of the earth causes warm air to rise, creating convection cells which form hurricanes.
Increasing temperatures increase evaporation, which leads to increased rainfall and therefore flooding.
How does deforestation and land degradation contribute to disasters?
People need farmland which increases flooding and soil erosion.
Coastal areas are developed on causing mangrove destruction an coastal erosion.
How does urbanisation contribute to disasters?
Development on squatter settlements on areas at risk of landslides or flooding.
How do poverty and politics contribute to disasters?
Developing countries can’t afford early warning systems etc…
Poorly educated people make it harder to prepare for disasters.
Difficult to get aid to places with poor infrastructure.
Corrupt governments may mis use resources or prevent international aid.
How has rapid population growth contributed to disasters?
Pressure on land forcing people to live in high risk areas.
Growing number of elderly people.
In developing countries there is a growing number of very young.
Why do volcanoes occur at hotspots?
Plume of magma rises from the mantle and goes through a tectonic plate.
Why do volcanoes occur at constructive plate boundaries?
Tectonic plates move apart causing plumes of magma to rise.
Why do volcanoes occur at destructive plate boundaries?
Oceanic crust is destroyed and subduction occurs, dense oceanic plate melts causing magma to viscously rise.
Why do landslides occur?
Forces operating down a slope exceed those resisting.
Steepening of slopes from erosion.
Heavy rainfall, flooding, snow.
Deforestation removing roots and weakens soil.
Why do droughts occur?
Variations in the movements of the ITCZ.
El Niño can bring major changes to rainfall.
Changes in mid latitude depression tracks.
Human activity such as deforestation.
Why do tropical cyclones occur?
Develop in trade wind belts.
There has to be… High humidity, light winds, temperature of oceans a 26degrees and be 60m deep.
Why do earthquakes occur?
Radioactive decay in earths core causes convection currents to ascend and descend. These cause slow movements from tectonic plates.
Friction builds up from them moving against each other.
When friction is released, plates joint causing earthquake.
What is La Niña?
Unusually high air pressure over South Western American Coast bad low over northern Australia.
Easterly trade winds more intense than normal.
More warm water is pushed west of the Pacific Ocean.
What are constructive plate boundaries?
Boundary between plates where the plates are diverging.
What are destructive plate boundaries?
Boundary between plates the plates are converging.
Conservative plate boundary?
Boundary between plates where movement is parallel to the plate margin and the plates slide past each other.
What is El Niño?
Unusually low air pressure over southwest America and high over Northern Australia.
Normal east to west trade winds over Pacific are disrupted.
Upwelling of cold water on the South American Coast is suppressed.
How does dependence on technology increase vulnerability?
We rely on technology to protect us from hazards. Eg early warning systems.
If and when these systems fail then we are unable fend for ourselves when a disaster happens.
Why is capacity to cope decreasing?
Communities need money to cope with the effects of climate change.
Unfair traded agreements and debt etc… Mean that the poorest and most vulnerable communities lack these resources.
Remaining exposed to hazards: changing risks
Difficult to predict when or where an event may occur.
Hazards vary due to human and physical activity.
Eg. Deforestation and tectonic plate movements.
Remaining exposed to hazards: lack of alternative
Often the worlds poorest people have no choice but to live in dangerous areas such as hillsides or flood plains.
Remaining exposed to hazards: benefits versus costs
The benefits of fertile land on a volcanically active area for example may outweigh the relatively low risk of a volcano.
Remaining exposed to hazards: risk perception
People tend to be optimistic about the chances of risks occurring.
Statistics showing that a hazard is unlikely comfort people.
They also think that because a happened has recently occurred that it won’t happen again for many years.
