Option Theme - Hazards and Disasters Flashcards
Disaster
A major hazard event that causes widespread disruption to a community or region that the affected community is unable to deal with adequately without outside help
Hazard
A threat (natural or human) that has the potential to cause loss of life, injury, property damage, socioeconomic disruption or environmental degradation
Hazard event
The occurrence (realisation) of a hazard, the effects of which change demographic, economic and/or environmental conditions
Risk
The probability of a hazard event causing harmful consequences (expected losses in terms of deaths, injuries, property damage, economy and environment)
Vulnerability
The susceptibility of a community to a hazard or to the impacts of a hazard event
Areal extent
The size of the area covered by the hazard
Small scale (avalanche) to continental (drought)
Spatial concentration
Distribution of hazards over space, whether they are concentrated in certain areas (tectonic plate boundaries, coastal areas)
Speed of onset
Time difference between the start of an event and the peak of an event
Rapid events (Kobe earthquake)
Slow timescale events (drought in the Sahel)
Regularity
Some hazards are regular (e.g. tropical cyclones) whereas others are random (e.g. earthquakes)
What is the focus?
The focus refers to the place beneath the ground where the earthquake takes place
What are deep-focus earthquakes ?
Deep-focus earthquakes are associated with plate margins where the oceanic plate is forced under the continental plate, in a process know as subduction
Where are shallow-focus earthquakes generally located?
Shallow-focus earthquakes are generally located along constructive and conservative boundaries
What is the epicentre?
The epicentre is the point on the ground surface immediately above the focus
What types of human activities cause earthquakes?
- nuclear testing
- building large dams
- drilling for oil
- coal mining
How are earthquakes caused at conservative boundaries?
As plates slide past each other, friction between them causes earthquakes. These are rare but very destructive
How are earthquakes caused at constructive boundaries?
Earthquakes are caused by friction as the plates tear apart. These earthquakes are small and don’t do much damage
How are earthquakes caused at destructive boundaries?
Sinking oceanic plate can stick to the continental plate. Pressure builds up against the friction. When the plates finally snap apart a lot of energy is released as an earthquake. They can be devastating, especially if shallow
Give an example of a conservative plate boundary
The San Andreas Fault
Why are tectonic hazards increased in developing countries?
People live in risky locations as there’s nowhere else to live
Can’t afford safe well-built homes so often buildings collapse
They don’t have insurance
Governments don’t have money and resources to provide aid
Poor communications so warning and evacuation may not happen
What are the focus and epicentre of an earthquake?
An earthquake starts at the focus. The epicentre is the point on the Earth’s surface above the focus and is the first place to shake
What happened in the Nigata (Japan) earthquake in 2007?
In city of 90,000, 11 people died + 1000 injured
350 buildings destroyed
Tsunami warning issued but false alarm
Epicentre offshore so less shaking on land
Happened at 6pm - people alert and remembered drill
What happened in the Kobe (Japan) earthquake in 1995?
City of 1.5 million - very high population density
5000 died and 26,000 injured
Many fires started and couldn’t be reached due to collapsed buildings
Damage was $200 billion
Epicentre was close to Kobe
Happened at 6am - people were asleep and confused in the dark
Name 3 features of earthquake contingency planning in Japan?
Every year Japan has earthquake drills
Emergency services practise rescuing people
People keep emergency kits at home containing water, food, a torch and radio
Name 6 features of an earthquake proof building in a developed country
Damper in roof acts like pendulum reducing building sway
Shock absorbers built into cross braces
Strong double glazed windows stop broken glass showering down
Very deep foundations to prevent collapse
A strong steel flexible frame prevents cracking
Cross bracing stops floors collapsing
When and where did the Sichuan earthquake occur?
In a province in central China on 12 May 2008
What were the primary impacts of the Sichuan earthquake?
Magnitude 8.0 earthquake 70,000 people died 400,000 people injured 5 million people made homeless up to $75 billion in damage
What were the local responses to the Sichuan earthquake?
Heavy rain, landslides and aftershocks made rescue effort very difficult
50,000 soldiers sent to help dig for survivors
Helicopters issued to help reach isolated areas
Chinese people donated $1.5 billion in aid
What were the international responses to the Sichuan earthquake?
UK gave $2 million
Finland sent 8000 tents
Indonesia sent 8 tonnes of medicine
Rescue teams flew in from Russia, Hong Kong, South Korea and Singapore
Name 5 features of an earthquake proof building in a developing country
- Cross braced wood or bamboo frame
- Concrete ring ties the walls to the foundations
- Lightweight thatch roof
- Walls made of mud and straw packed between wooden slats
- Simple steel rod foundations
What may be the cause of isolated occurrences of earthquakes (not along plate boundaries)?
- human activity
- isolated plumes of tectonic activity known as hotspots
What is liquefaction?
Loose materials e.g. soil may act like a liquid when shaken (in an earthquake). Solid rock is much safer, and buildings built on flat areas of solid rock are more resistant
What are 4 things to observe when predicting and monitoring earthquakes?
Crustal movement - small-scale movement
Changes in electrical conductivity
Strange + unusual animal behaviour (esp. carp fish)
Historic evidence - whether there are trends in the timing of earthquakes in a region
What conditions are needed for hurricanes to form ?
Sea temperatures = at least 27 degrees to a depth of 60metres
Low pressure area has to be far enough from the equator to allow the Coriolis force to create rotation in the rising mass of air
Conditions must be unstable
What is the Saffir-Simpson scale?
The Saffir-Simpson scale assigns hurricanes to 1 of 5 categories of potential disaster. The categories are based on wind intensity. Only used in Atlantic + northern Pacific
How many earthquakes happen a year in the UK?
200 on average
Ramsgate earthquake 22 May 2015
- 4.2 magnitude
- epicentre 1.4 miles off the coast of Ramsgate
- no deaths
- occurred at around 3am
- little infrastructural damage
Hurricane Mitch // key information
- Formed over Caribbean Sea
- Hit Central America in 1998
- Reached wind speeds of 180mph
Hurricane Mitch // how was a tropical depression formed?
A very hot summer meant sea temp. reached 27degrees
This meant a lot of evaporation of water vapour
Causing air above sea to become humid + damp
Air above sea is so hot it rises
This causes an area of low pressure to form
Air was sucked in over the sea to replace the rising air
Therefore a tropical depression was formed
Hurricane Mitch // how did it become a hurricane?
Winds became increasingly stronger as air rose more rapidly
Meaning movement of air to replace it became faster also
As a result air started to spiral as well as increase in speed
Mitch became a tropical storm and then a hurricane on 23 October 1998
Hurricane Mitch // impacts on landscape // in Honduras?
Trees flattened
Power lines knocked over
Vast quantities of rain in short period of time washed oil into rivers, blocking them
Resulting widespread floods destroyed bridges + roads
Hurricane Mitch // impacts on landscape // in Nicaragua?
Rain caused mudslide on Casita volcano
This completely buried 4 bridges
Hurricane Mitch // impacts on people
Approx. 9000 people died Many made homeless Farmland destroyed Spread of water-borne diseases National debt increased due to cost of repairs
Hurricane Mitch // prediction
Hurricane Mitch changed direction frequently + suddenly so hard to predict where it would make landfall
Warnings given to many countries in Central America so many people fled inland
Hurricane Mitch // short term aid
GOVERNMENT TROOPS helped rescue those stranded by floods or trapped in rubble
MEXICO and USA sent helicopters + troops to help
HELICOPTERS took supplies to remote areas and airlifted injured to hospital
THE RED CROSS provided water purification kits
Hurricane Mitch // long term aid
UN provided seeds, tools + fertilisers to rural areas
AID AGENCIES provided funds to build new schools, hospitals, roads and homes
Hurricane Mitch // effectiveness of response
- Many were saved who otherwise would not have survived
- THE RED CROSS successful in keeping disease to a minimum
- Long term aid stopped when Mitch not featured so heavily in news // redevelopment also stalled
Cyclone Nargis, Burma (May 2008) // impacts
- winds exceeded 118mph
- torrential rain killed 134,000 people
- 95% of all buildings in affected area demolished by cyclone and resulting floods
- in some towns, 70% population was dead or missing
Cyclone Nargis, Burma (May 2008) // what factors made the cyclone more damaging ?
Disaster management experts failed to get the necessary visas to enter the country
Corruption meant aid may not have reached citizens
Government rejected international aid
What is drought?
A drought is an extended period of dry weather leading to extremely dry conditions
Drought case study: Ethiopia // location
East Africa
Landlocked (continentality limits amount of water carried by winds)
Drought case study: Ethiopia // when
- between 1984-5
- in year 2000
Drought case study: Ethiopia // causes
- In 2000 and 1984-1985 there had been poor rainfall for 3 years. This caused crops to fail and also forced herdsman to slaughter their cattle.
- The lack of rain was due to cooler sea temperatures in the Atlantic & Pacific, so less evaporation occurred and hence less rain fell
- The population of Ethiopia had grown exponentially by 2000 meaning there was too little food to feed the population.
Drought case study: Ethiopia // impacts
- 1 million people were killed in both droughts.
- In the 1984 famine, 1 person died every 20 minutes due to undernourishment.
- The 2000 famine affected 43% of the population.
- The price of food during the 2000 famine rose greatly due to mass migration of farmers + livestock in search of water
Drought case study: Ethiopia // responses
- NGOs (Oxfam, MSF etc…) provided aid
- An early warning system was setup to predict poor rainfall so that food and aid can be acquired in preparation.
Drought case study: Europe 2003 // Portugal
Portugal declared state of emergency after the worst forest fires for 30 years
Temperatures reached 43 degrees in Lisbon in August 2003, 15 degrees hotter than average
1,300+ deaths occurred in first half of August
35,000 hectares of forest, farmland + scrub burned
What are technological hazards?
Technological hazards are generally seen as major man-made accidents, often leading to health + nutrition issues after exposure to chemical pollutants or low level hazardous waste
Case Study: Bhopal disaster (1984)
- 3 December 1984
- Bhopal, India
- Union Carbide pesticide plant release 40 tonnes MIC gas
- Immediately killed 3000
- Ultimately killed between 15,000 - 22,000
- Considered world’s worst industrial disaster
Case Study: Chernobyl (1986) // what happened
- 26 April 1986
- Worst nuclear disaster ever
- A few miles north of Kiev
- An explosion and then fire resulted in a level 7 event (the highest) in reactor 4
- The reactor went into meltdown and a cloud of highly radioactive material drifted over much of Russia and Europe, even reaching Wales + Scotland
- Fission products have a long half-life and were accumulated in food chains
Case Study: Chernobyl (1986) // impacts
- 31 people died immediately due to radiation
- Some estimates state that 1 million people will have died as a result of the disaster
- However it is difficult to know for certain as long-term illnesses e.g. cancer are difficult to pin-point to a particular event
- 130,000 evacuated from surrounding regions
- In 2009, there were still restrictions on selling sheep from some Welsh farms due to their levels of radiation
Case Study: Chernobyl (1986) // did the authorities in USSR announce the disaster?
The authorities did not announce the disaster. It was picked up in Sweden when fallout was found on the clothing go workers at one of their nuclear plants
Case Study: Chernobyl (1986) // relief efforts
- 400,000 workers needed to clean up the plant
- A huge sarcophagus constructed to cover reactor
- New sarcophagus in 2015 built to contain waste
Case Study: Chernobyl (1986) // how could management of the disaster have been more effective ?
- Russia should have alerted world leaders as soon as disaster became apparent
- Immediate evacuation of everybody inside 30km exclusion zone
- Better training for staff
- During construction, ensured backup systems e.g. pump under plant to drain water
Why do millions of people live in river floodplains?
- During a ‘normal’ year the river may not flood
- River provides opportunities for transport + recreation
- Potential for trade + communications
- River deltas have particularly fertile soils
Why do people live in volcanic environments?
- Provide rich, productive soils
- Provide minerals to mine
- Attraction for tourists
How has industrialisation + urbanisation lead to increased hazards?
- In megacities the volume of vehicles on roads leads to decline in in air quality
- Concentration of manufacturing industry (in southeast China) has lead to decline in air quality, water pollution + increased acidification
How can you calculate risk?
Risk = Hazard + Vulnerability
What are the root causes increasing vulnerability ?
LIMITED ACCESS TO
- power
- structures
- resources
IDEOLOGIES
- political systems
- economic systems
What are the dynamic pressures increasing vulnerability ?
LACK OF
- local institutions
- training
- appropriate skills
MACRO-FORCES
- rapid population growth
- rapid urbanisation
- deforestation
Case study: Social vulnerability and Hurricane Katrina // background information
- New Orleans is built on land below sea level
- Many homes were submerged by the floodwater brought on by the storm
- New Orleans’ levées gave way under pressure of storm
- Most of city went under water, some areas 6m under
- One of worst affected areas was the poor district of Ninth Ward
Case study: Social vulnerability and Hurricane Katrina // what were the impacts of the storm
- Floodwaters 10x more toxic than considered safe
- People with cars able to evacuate before Katrina hit
- Of 1800 people killed + 800,000 made homeless, the great majority were from poor ethnic minorities
Case study: Social vulnerability and Hurricane Katrina // why was the rescue operation criticised ?
- Rescue operation criticised for not doing enough to help poorest members of population
- Most of those left without help were from poor neighbourhoods, which were worst hit by Katrina
- The disproportionate impact on the poor highlight existing racial + class inequalities in USA
Case study: Social vulnerability and Hurricane Katrina // Impact and social status of damage (statistics)
- In disaster area 20% households had no car
- 25% of those living in worst affected areas below poverty line
- 60% of people affected were from an ethnic minority
Case study: Haiti earthquake Jan 2010 // causes
- 12 January 2010
- Caused by the North American Plate sliding past the Caribbean Plate at a conservative plate margin
- Both plates moved in same direction, but one faster
- The pressure built up due to friction between the 2 plates was eventually released
- Caused magnitude 7 earthquake on Richter Scale
- Epicentre 16 miles West of Port-au-Prince (densely pop.)
- Shallow focus of 5 miles.
Case study: Haiti earthquake 2010 // primary effects
- 316,000 killed
- 1 million homeless
- Transport + communication links badly damaged
- Main prison destroyed + 4000 inmates escaped
Case study: Haiti earthquake 2010 // levels of poverty
- 80% people live on $2 or less a day
- Only 46% have access to clean water
- Earthquake was major setback in economic + social advancement
- In 2006, Haiti’s HDI was 0.475
- By 2013 it had lowered to 0.471
How can technology help when predicting hurricanes?
- Satellites detect hurricanes in early development stage
- Reinforced aircraft w. instruments fly through hurricanes
- Weather radar can locate storms within 320km of radar station
What are 5 factors that tend to increase risk perception?
- Involuntary hazard
- Direct impact
- Uncontrollable hazard
- Lack of belief in authority
- Unfamiliar hazard
In what ways is it possible to modify the hazards for earthquakes and hurricanes?
EARTHQUAKES
- soil + slope stabilisation
- sea wave barriers
- fire protection
HURRICANES
- wide belts of forest to reduce wind speeds
- build back from coast
what ways is it possible to modify loss potential for earthquakes, volcanoes and hurricanes?
- warning systems
- emergency evacuation and preparation
What is the difference between a hurricane watch and a hurricane warning ?
- A hurricane watch is issued when there is a threat of a hurricane within 24-36 hours
A hurricane warning is issued when hurricane conditions are expected within 24 hours
What are 3 things you should do during a hurricane watch?
- Listen to radio for hurricane progress reports
- Check emergency supplies
- Fuel car
What are 3 things you should do during a hurricane warning?
- Take blankets + sleeping bags to shelter
- Listen constantly to radio for official instructions
- Stay inside, away from windows + glass doors
What are 2 things you should do after a hurricane?
- Assist in search and rescue
- Seek medical attention if injured
What is rescue?
Saving people so they can survive despite only having minimum life necessities
What is rehabilitation?
Restoring the functions of public services, process that needs one or two years
What is reconstruction?
Rebuilding the public system, economic system, infrastructure and governance functions. Predicted to take 2-5 years
