The Challnege of Natural Hazards Flashcards
What is a natural hazard?
A natural event that could cause damage to people or property
What is hazard risk?
The probability of being effected by a natural event
Name 6 examples of naturals events
Volcanic eruptions
Earthquakes
Storms
Tsunamis
Landslides
Floods
Outline the 4 factors effecting hazard risk
Urbanisation
Poverty
Climate change
Farming
How will urbanisation increase hazard risk
Some of the worlds largest cities are at risk of different natural hazards. Densely populated cities in hazardous areas have greater hazard risk
How will poverty increase hazard risk?
In poorer parts of the world poverty may force people to live in areas at risk. Such as on slopes, near rivers.
How will climate change increase hazard risk?
In a warmer world there is more energy leading to more intense storms. Also increase chances of flooding and drought
How will farming increase hazard risk?
Rivers deposit fertile silt on floodplains which is excellent for farming. People put themselves at risk to farm this land
What are tectonic hazards?
Natural hazards cause by the movement of tectonic plates
What is the relationship with earthquakes and tectonic plates?
Most earthquakes occur along tectonic plates due to a release in energy built up by friction. Earthquakes not on tectonic margins are caused by human activity
What is the relationship with volcanoes and tectonic plates?
Volcanoes are made by constructive and destructive plate margins aswell as hot spots where the crust is thin and magma can break through
Where are most volcanoes found?
Around the Pacific Ocean or ‘pacific ring of fire’ and mid Atlantic ridge
Outline the three types of plate margin.
Constructive
Destructive
Conservative
Describe a destructive plate margin.
Two plates moving towards eachother. When a continental and oceanic plate meet the denser oceanic plate is subducted beneath the less dense continental plate. Friction causes strong earthquakes and as the subducted plate melts the magma creates volcanoes
When two continental plates meet there is no subduction and instead folds of mountains form
What is an example of a destructive plate margin.
Oceanic Nazca plate and continental South American plate
Describe a constructive plate margin
Two plates moving apart so magma forces its way up the surface, as it breaks through it causes earthquakes.
What is an example of a constructive plate margin?
Along the mid Atlantic ridge
Describe a conservative plate margin
Two plates moving past each other. Friction builds up along margins and as stress builds over many years energy is released and the plates slip and shift.
What is an example of a conservative plate margin?
The San Andreas fault
Outline the 4 ways to reduce risk of tectonic hazards
Monitoring
Prediction
Planning
Protection
Describe how monitoring can reduce tectonic risk?
Using scientific equipment to detect warning signs of events such as volcanic eruptions. This includes measuring natural gas, detecting heat with satellites and changes in landscape
Describe how prediction can reduce tectonic risk?
Using historic evidence and monitoring can make predictions about when a tectonic event might happen.
Describe how protection can reduce tectonic risk?
Designing buildings and structures that can withstand tectonic events. Constructing buildings with shock absorbers and reinforced foundations
Describe how planning can reduce tectonic risk?
Identifying and avoiding places at risk where volcanoes and earthquakes are lost common.
Why do tectonic plates move?
Because of convection currents in the mantle
What are the two types of natural hazard?
Geological and meteorological