The Challenges Of Natural Hazards Flashcards
What are natural hazards
Physical events such as earthquakes and volcanoes that have the potential to do damage to humans and property.
What affects hazard risk?
-population growth
-climate change
-deforestation
-LIC’s are at more risk because they don’t have the money to protect themselves
Structure of the earth
-the core
-mantle
-crust
Crust
Split into major sections called tectonic plates.
Crust
-oceanic and continental crust
-these plates move due to convection currents in the mantle and where they meet volcanoes and earthquakes occur.
Margins
-destructive when they move towards each other
-constructive when they move away from each other
-conservative when they move past each other
Volcanoes
Constructive margin - hot magma rises between the plates
Destructive margin - an oceanic plate subducts under a continental plate to melt and pressure forces magma up to form composite volcanoes
Earthquakes
Constructive margin - small earthquakes as plates pull apart
Destructive margin - violent earthquakes as pressure builds and is then released
Conservative margin - plates slide past each other. They catch and then as pressure increases it is released
Primary and secondary effects of earthquakes
Primary- property of buildings destroyed
- people injured or killed
- damaged services
-water, gas and electricity broken
Secondary- money lost repairing buildings
-blocked transport
-broken gas pipes cause fires
-broken water pipes lead to lack of fresh water
Primary and secondary effects of volcanoes
Primary- property and farms destroyed
-people and animals killed and injured
-water supplies contaminated
Secondary- emergency services struggle to arrive
- ash breaks down leading to fertile land
Immediate responses to hazards
-issue warnings
-rescue teams
-treat injured
-provide shelter
-extinguish fires
Long term responses to hazards
-repair and rebuild properties
-restore utilities
-resettle locals elsewhere
Distribution of tectonic activity
Along plate boundaries on the edge of continents and around the edge of the pacific.
Monitoring
Seismometers measure earth movement.
Volcanoes give off gases
Prediction
By observing monitoring data, this can allow evacuation before event.
Protection
Reinforced buildings and making building foundations that absorb movement.
Automatic shut offs for gas and electricity.
Planning
Avoid building in areas at risk.
Training for emergency services and planned evacuation drills.
Nepal earthquake 2015 April - primary effects
-magnitude 7.8
-9000 deaths
-23000 injured
-500,000 homes destroyed
-26 hospitals destroyed
-50% of schools destroyed
Nepal earthquake- secondary effects
-avalanche on mountain killing 19 people
-loss of tourism and income
-food shortages
Nepal - immediate response
-raised $126 million
-red cross
-requested international help
-tents for 225,000 people
Nepal - long term response
-international conference to discuss reconstruction
-tourist attractions reopened
Global atmospheric circulation
At the equator the suns rays are most concentrated this means it is hotter.
High pressure = dry
Low pressure = wet
As the air heat rises - causing low pressure as it cools it sinks causing high pressure. Winds move from high pressure to low pressure. They curve because of the coriolis effect.
Tropical storms
In low latitudes between 5 and 30 degrees north and south if the equator. Ocean temperatures needs to be above 27 degree and between summer and autumn.
Sequence of a tropical storm
-Air is heated above warm tropical storms.
-Air rises under low pressure conditions
-strong winds form as rising air draws in more air and moisture causing torrential rain
-Cold air sinks in the eye so it is clear and dry
-heat is given off as it cools powering the storm
-on meeting land it loses source of heat and moisture so loses power
Climate change will affect tropical storms to. Warmer oceans will lead to more intense storms – but not necessarily more frequent ones

Extreme weather in the UK
– Can cause flooding damaging homes and businesses
– Causes damage to properties and crops
– Lightning can cause fires or even death
– Heat waves cause breathing difficulties and can disrupt travel
Weather is getting more extreme due to climate change. Temperatures are more extreme and rain is more frequent and is leading to more flooding events.
2003 UK heat wave
A heat wave bringing record temperatures to the UK hit in August 2003. Highest temperature was recorded in Kent
Social economic and environmental effects on the heat wave
Social – 2000 UK deaths
-drinking water supplies were affected in some parts of the UK and hosepipe bans introduced
Economic – some railway tracks buckled in the heat. The London underground became unbearable. Some road services melted. Low river levels prevented some boats from sailing.
Environmental – it is thought that one third of the deaths caused by the heat wave in the UK were caused by poor air quality.
Management strategies on the heat wave
– Met office issued weather warning
– Network rail in the UK imposed speed restrictions for trains when the temperature was above 30°
Natural causes of climate change
– The suns energy on the Earth surface changes as the earths orbit is elliptical its axis is tilted on an angle
– Volcanic aerosols reflect sunlight away reducing global temperatures temporarily
Human causes of climate change
– Fossil fuels release carbon dioxide with accounts for 50% of greenhouse gases
-greenhouse gases from methane
– Deforestation reduces ability to plants to absorb carbon through photosynthesis
Social and environmental effects of climate change
Social
– Droughts
– Melting ice caps
– Increased skin cancer risk
Environmental
– Sea levels rise
– Warmer rivers affect marine wildlife
Mitigation
– Alternative energy production will reduce CO2 production
– Planting trees helps remove carbon dioxide
– Carbon capture takes carbon dioxide from emission sources is stored underground
Adaptation
– Managing water supplies by installing water efficient devices and increasing supply through plants
– Thames flood barrier reduces risk of flooding from rising sea levels
Chile HIC earthquake causes
on a destructive plate margin the Naza plate subducts under the South American plate
magnitude: 8.8
Chile earthquake effects
Primary:
- 500 deaths, 220,000 homes destroyed. Loss of power/water supplies
Secondary:
- 1500km roads damaged by landslides, coastal towns effected by tsunamis
Chile earthquake response
Immediate response:
- emergency services quick to respond, highway repaired so aid could get through
Long term response:
- Government launched a housing reconstruction plan
Typhoon Haiyan effect
- 6500 deaths
- 130,000 homes destroyed
- water and sewage systems destroyed causing diseases
Typhoon Haiyan response
- The UN raised £190mil in aid
- Helicopter delivered aid to remote areas
- Oxfam replaced fishing boats
volcanic hazards
ash cloud - small pieces of rock and glass that are throw into the atmosphere
gas - sulphur dioxide, water vapour, and carbon dioxide come out of the volcano
lahar - volcanic mudflow which flows down volcano valley
volcanic bomb - lava fragment that is ejected from the volcano
Somerset floods effects
- 600 houses flooded
-16 farms evacuated - roads cut off
- sewage mixed with water
- cost £10mil
Somerset floods management
- river banks built up
- more pumping stations
- £20mil flood action plan
