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
What is the global atmospheric circulation system?
A system of winds and pressures effected by the global temperature
How is an area of low pressure created on the equator?
The sun warms up the Earth which heats up the air above, causing it to rise.
What is the properties of a low pressure area and how are they made?
They are made as heat rises and they cause clouds and rain
What are the properties of a high pressure area and how are they formed?
As cool air sinks they are made and they create cloudless skies and very low rainfall
At what degrees do you find area of high pressure?
30 degrees north or south
At what degrees do you find areas of low pressure?
On the equator or at 60 north or south
What is the name of a cell between 60 and 90 degrees?
Polar cell
What is the name of a cell between 60 and 30 degrees?
Ferrel cell
What is the name of a cell between 0 and 30?
Hadley cell
What are the three types of tropical storm and where are they found?
Cyclone - Australia and se Asia
Typhoon - around Japan and the Philippines
Hurricane - Around America and Caribbean
Where do tropical storms form?
Normally on the tropics as they form over warm oceans above 27 degrees
At what degrees do they form and why?
Normally between 5-15 degrees north or south, they cannot form on the equator as there is no coriolis effect
What are the 6 steps to a tropical storm?
- A strong upward movement of air draws up water vapour.
- This evaporated air cools to form thunderstorm clouds
- As air condeses it releases heat which powers the storm and draws up more vapour
- Several of these small storms join together to form a big spinning storm and when winds average 125kph it is officially a tropical one.
- The storm develops an eye where air descends
- The storm is carried across the ocean by winds and as it passes over land it’s power supply is cut off and it weakens.
What are the two main features of a tropical storm?
An eye - where cold air sinks - calm conditions, no clouds
An eye wall - tall banks of clouds - torrential rain and 120km+ winds
In what three ways may climate change effect tropical storms?
Distribution
Intensity
Frequency
How many climate change alter the distribution of tropical storms?
As patterns of sea surface temp change more of the ocean could be effected by storms as more may exceed 27 degrees
How many climate change alter the intensity of tropical storms?
Increase surface temperatures mean tropical storms may be stronger and have more power
How many climate change alter the frequency of tropical storms?
More of the ocean will be warmer for longer which may cause tropical storms to occur out of the normal seasons
What is the tropical storm case study?
Typhoon Haiyan
What are the four ways the effects of tropical storms can be reduced?
Monitoring - monitoring storms to get early warnings
Prediction - using data from monitoring to calculate a storms path
Planning - future developments can be planned away from risk
Protection - buildings can be made from reinforced concrete and flood defences
Outline and explain weather hazards in the UK.
Rain - can cause flash flooding
Wind - damage to properties and possible injury
Snow and ice - injuries due to slippage and could cause closures
Thunderstorms - lightning could cause fire
Heat waves - heat exhaustion, disruption to transport
Drought - death to crops and lack of water
What is some evidence for extreme weather in the UK?
Temperatures more extreme - Dec 2010 coldest in 100 years
More rain - rainfall records broken in 2010-2014
Major flooding such as Somerset levels and Cumbria in 2012, 2005 +
Heatwave - 2022 hottest summer on record with temp hitting 40
What are four pieces of evidence for climate change?
Ice and sediment cores - analysising gases trapped in ice and the remains of organisms
Pollen analysis - pollen gets preserved and pollen can be tested back to a species to see what the conditions must have been
Tree rings - things of rings change with different weather conditions
Temp record - since 1850 there has been a reliable global temp record
Outline 3 natural climate change factors.
Orbital changes
Volcanic activity
Solar output
Explain how orbital change effects climate change.
Changes in how the earth orbits the sun can change where and how much solar radiation hits the earth
Explain how volcanic activity could cause climate change
Volcanoes eject materials into atmosphere that could reflect suns rays so the surface cools
Explain how solar output could cause climate change.
The suns energy output changes and different periods could cause different global temps
What is axial precession?
The 26000 year cycle of the earth wobbling
What is axial tilt?
The 41000 year cycle where earth tilts between 21.5 and 24.5 degrees
What is changes in eccentricity?
100000 year cycle where earths orbit goes elliptical
Outline three human causes to climate change?
Fossil fuels
Agriculture
Deforestation
Explain how fossil fuels could cause climate change
Produce nitrous oxides that are 300 times more effective at capturing heat that carbon dioxide
Explain how deforestation could cause climate change
Releases carbon dioxide when cutting and burning trees and wood. Trees also don’t use as much carbon dioxide
Explain how agriculture could cause climate change
Produces methane from livestock and rice farming accounts for 20% of greenhouse gases
How can climate change be managed(mitigated)
Renewable energy production such as HEP
Carbon capture - capturing and storing condensed carbon in rock
Planting trees - act as carbon sinks, remove carbon dioxide
How can climate change be managed (adaptation)?
Change in agriculture - drought resistant crop and changes in where crop is grown
Managing water supply - storing water
Reducing risk from sea levels - coastal defences and restoration
What is the name of an example to manage water supply as a impact of climate change?
Managing water su Himalayas
What is the name of an example to manage rising sea levels as a impact of climate change?
Rising sea levels in the Maldives
How is water supply being managed in the Himalayas and why is it necessary?
Millions depend on rivers fed by slow and glacial melt.
Most of the Himalayas’ glaciers are receding rapidly
They are using artificial glaciers to supply water to villages
Water is collected in the winter and frozen, when it melts in the spring it will provide water
How are rising sea levels being managed in the Maldives and why is it necessary?
The Maldives are a group of tiny islands in the Indian Ocean
Highest point is just 2.4m above sea level
380000 inhabitants
They are restoring the coastal mangrove forests to offer protection
Constructing 3m high sea walls
Building raised houses
