Case studies Flashcards
Asian Tsunami 2004
- caused by an earthquake on the 26th december
- caused by the subduction of the denser oceanic australian plate under the continental eurasian plate
- billions of tonnes of sea water displaced
- magnitude of 9.0 and lasted for over 4 minutes
- 30km deep focus (shallow)
- hit the coast of Indonesia half an hour after eq
- water was travelling at around 50mph but slowed down in shallower water, increasing height
- little prediction systems
- no ocean sensors or water level sensors
- tsunami warning system in the pacific alerted of the eq however only 2 of 11 impacted countries belonged to the system
impacts
primary
- 250,000 killed in 14 countries
- over 500,000 injured
- 1.7 million left homeless
- serious infrastructure damage
- water sources contaminated
- $10 billion in damage
secondary
- 1 million left unemployed
- aftershocks
- tourism economy badly damaged
- loss of fishing boats
- diseases like cholera and dysentery spread
responses
short term
- people fled to higher ground
- bodies buried in mass graves to prevent disease spread
- governments provided over $7 billion in aid and cleanup
- temporary shelter provided
long term
- tsunami early warning system installed
- whole towns rebuilt
- community homes and orphanages set up
Japanese Tsunami 2011
- japan is the meeting point of 3 tectonic plates
- japan experiences many earthquakes due to the pacific plate being subdued under the eurasian plate
- 7.2 magnitude earthquake followed by a 9.0 magnitude earthquake 2 days later
- after shocks of up to 6.0
- produced a 40m tsunami travelling 10km inland
- japan is relatively well prepared
- 40% of coastline has sea walls of 10m
- japan is trained every year on how to survive earthquakes
- many buildings are earthquake proof
- agency detected the eq and sent warnings out
- coast is most vulnerable area
- fukushima nuclear power station was directly in line with the epicentre
impact
- 15,749 killed
- 26,992 injured
- 130,000 buildings collapsed
- 500km2 of land damaged
- fukushima had released of radioactive material causing contamination
- $235 billion in damage
responses
short term
- military was sent to help civilians
- shortages of food and water
- rescue teams sent out from other HIC countries
- people evacuated
long term
- infrastructure like motorways repaired
- temporary housing built
- small coastal areas raised
- small businesses given grants to recover
Eyafjallajokull Volcano 2010
- volcano at the divergent plate boundary of the NA plate and the Eurasian plate
- 4 on the VEI
- lava launched 150m into air
- caused major flood as destroyed glacier covering volcano
- some warning signs despite long time since last eruption
- 3000 earthquakes in the area before eruption
- area was prepared
- Met office in Iceland monitored earthquakes
- no deaths or injuries
- people had to wear goggles and face masks due to ash
- led to a flood causing 700 people to evacuate
- contaminated soils and livestock
- 3,000 tonnes of CO2 but had little impact on climate
- major impact on air travel in the region and in europe (100,000 journeys cancelled)
- £130 million lost a day from airlines
- affected world trade
Mount Pinatubo, Philippines 1991
Volcano
- on convergent plate boundaries where the oceanic plate is being subdued under the eurasian plate
- part of the pacific ring of fire
- preceded by mini earthquakes and sulphur dioxide releasing from the volcano
- 8 days before the eruption a lava dome extruded
- 15th june eruption
- pyroclastic flows and a 22 mile ash cloud
- the US and philippines predicted the eruption saving 5000 lives and $250 mil in damages
- lahar detectors and hazard maps showing vulnerable areas
impacts
- 364 communities and 2.1 mil people affected
- 847 killed: 300 from collapsing roads, 100 from lahars and 447 from disease
- 100,000 made homeless
- 1 million farm animals starved to death
- $700 million in damages
- $40 million in agricultural losses
- 200,000 acres of farm land destroyed
responses
- US airforce helicopters helped with evacuation
- evacuation camps set up
- red cross, organ and HICs helped to provide aid
- millions of £ sent by EU countries for relief and rehabilitation
- aeta people resettled
- new houses placed on stilts
- dikes and dams constructed to help prevent lahar flows
Haiti Earthquake 2010
- country lies on the boundary of the caribbean and north american coast plates
- one of the poorest countries in the world
- 86% of people living in capital city live in slum conditions
- governance is weak and corrupt
- 7.1 magnitude
impacts
- 160,000 people died
- bodies bulldozed into mass graves to prevent disease
- 300,000+ injured
- 1.5 million became homeless
- cholera outbreak
- $11.5 billion in damages (120% of haitis GDP)
responses
- Dominican republic provided emergency water and medical supplies as well as machinery
- emergency rescue teams arrived from abroad
- after one year there were still 1300 refugee camps
- schools are being rebuilt
- cash for work schemes are paying haitians to help clear rubble
Christchurch, New Zealand 2010/11
Earthquake
- slippage along the conservative boundary between the indo-australian and pacific plate
- not predictable
- 6.3 magbitude
- low vulnerability
- vulnerable to liquefaction (eq causing saturated soils to lose strength)
impacts
- 200 people injured
- 181 killed
- 50% of city’s central buildings damaged
- water supplies disrupted by burst pipes
responses
- red cross provided grants to families with children under 5 who were living in damaged homes
- $989 million paid in building claims
- temp housing provided
- urban search and rescue helped
- art gallery turned into emergency response centre as eq proof
- cardboard churches built
Jurassic coast
- 185 million years old in parts
- old harry & wife represent a cave-arch-stack-stump sequence
- lulworth cove formed after the ice age
The holderness coast
fastest eroding coastline in the UK due to:
- geology of boulder clay and glacial sands that make up large amounts of the coast
- power of the waves (hydraulic action and abrasion occur due to the long fetch that the waves have when they meet the coast)
- material in the sea being carried away by longshore drift
Mike Needly - Ringborough farm
- bought 145 acres in 1939
- due to erosion rates of 1-2 metres per year he now has half that
- has diversified to selling bottled natural gas to survive
- building and maintaining defences is expensive and may harm coast further down
- no money is given for loss of land
- Withernsea, Hornsea and bridlington have seen sea defences built as cost benefit analysis shows it is worth it
- defenses have been built in mappleton due to the risk of the loss of road that connects this village (defences cost £1.9 million in 1991) however this caused terminal groyne syndrome in the town of cowden
- Kilnsea east riding have not had defences built due to lack of funds
- local people have instead implemented flood drainage ditches which last 20 years
- sandy beaches caravan park has lost land due to a lack of defences, one storm caused 10m to be lost
- sediment cell concept
Dalmatian coast, croatia
- long narrow island running parallel to the coastline
- produced by sea level rise flooding the coastline with the geological structure of folds aligned parallel to the coast
- croatia has 520km of this
Aswan Dam and Nile delta
- Located in Egypt
- built in 1971
- controls the regular flooding of the nile and reduces the supply of sediment
- water supplies more reliable and electricity generated
- caused some types of fish to disappear
- 95% of population live here
Deltawerken, Netherlands
- hard engineering project following the 1953 storm surge
- series of gates to control the flow of water during a storm surge
- reduces the length of the coastline exposed to the sea
- cost more than $5 billion
- costs $1 billion a year to maintain
- allows 4 million people to live below sea level
- some nature reserves lost during construction
1953 and 2013 storm surges
context: low air pressure allows water to bulge up in a dome, the dome gets higher the lower the pressure
1953
- low pressure raised water levels, high northerly winds
- funnelled between england and holland
- 2.5 metres above sea level
- over 300 people died
- 24500 houses damaged
2013
- storm surges reached heights of 6.3m
- wide spread flooding
- low pressure, high winds, high tidal pressures combined
- 2 deaths in the uk
- 1400 homes flooded
- £1 billion in damage
- thames barrier protected some areas
Cycle Sidr, Bangladesh 2007
- 6m high storm surges and 223km/h winds
- 3500 fatalities due to drowning
- drinking water contaminated
- country is very low lying (1-3m abv sea level, 70% is less than 1m)
- storm funnelled through bay of bengal
- deforestation of mangroves meant little dissipation of wave energy
Tuvalu, Maldives
- example of environmental refugees
- average height of 1.5m above sea level, even lower in tuvalu
- highest point is only 4.5m above sea level
- coral reefs have been destroyed by increased wave energy and and global warming
- ground water sources are contaminated by salt water
- high population density
- 400,000 residents with nowhere to go
Medmerry
- managed retreat
- flooded farmers fields
- cost £28 million
Happisburg
- no active intervention (2004)
- population of 1400
- several houses lost on beach road
- funnel effect
- houses have low/no value
- coastal concern action group raised £3 million
- 67% agricultural, 22% residential, 6% public, 4% tourist, 1% commercial
winners: local government, some homeowners, local caravan parks
losers: tourists, residents, environment agency
Sea palling
- 150,000 tonnes of rock armour
- offshore bars constructed at a cost of £5.9 million
- 95% agricultural, 2% residential, 3% public, tourist and commercial
Chittagong, Bangladesh
Coastal management
- densely populated
- coastal climate resilient infrastructure project
- 60cm embankment raising
- 200 people displaced
winners: market owners, government, farmers
losers: displaced residents, environmentalists
amazon rainforest
- deforestation in the amazon has caused EVT rates to go from 75% to 25%
Australia drought
1. Physical Causes
• Climate Patterns: Australia’s climate is heavily influenced by the El Niño-Southern Oscillation (ENSO), which brings drier conditions during El Niño phases. • Low Rainfall and High Variability: Australia’s arid climate and inconsistent rainfall make droughts frequent, especially inland. • Climate Change: Rising temperatures increase evaporation and reduce soil moisture, making droughts more severe and frequent.
2. Human Causes
• Overuse of Water Resources: Extensive irrigation in areas like the Murray-Darling Basin and urban water demand deplete available water. • Land Use and Deforestation: Clearing land for agriculture reduces moisture retention, worsening drought effects. • Policy Gaps: Weak water management policies, especially in regulating extraction, have often led to overuse and misallocation of resources.
3. Impacts of Drought
• Environmental: Drought disrupts ecosystems, degrades water quality, and heightens bushfire risks, as seen in the severe 2019-2020 bushfire season. • Economic and Social: Drought impacts agriculture, leading to crop losses, higher food prices, and economic strain on farming communities, affecting livelihoods and mental health.
Hawaii Hotspots
hotspot volcano
Blackpool intraplate earthquake
earthquake in the middle of a tectonic plate in this case due to hydraulic fracking
Lahar example (not a mainstream case study)
1985 Nevada Del Ruiz
a hot mixture of water and rocks that flow out of a volcano into a river valley
lulworth crumple (jurassic coast) and king cave (isle of arran)
evidence of isostatic change and eustatic change
dorset coast
concordant and discordant coast
studland bay and durlston head
geology changes from clay to sands to chalk to limestone
UK floods 2015-16
- during the winter of 2015-16 northern parts of the UK were affected by a sequence of depressions causing prolonged periods of heavy rain
- storm abigail saturated soils, then desmond caused flooding with over a months rainfall in a day and then storm eva caused further flooding in the pennines
- over 16,000 properties in england were flooded
- the UK government provided £200 million for recovery and estimated costs were £5 billion
