Tectonic hazards case studies Flashcards
key impacts of Haiti earthquake
- 217,000 dead
- 300,000 injured
- one million homeless
- 3 million effected
- US$8 billion damage
- 1994
dates/duration of haiti earthquake
- 12th Jan 2010
- 4:53 pm
- less than 30 secs, 7.0 magnitude
plates involved in Haiti earthquake
- north American plate to the north and Caribbean plate to the south
- conservative boundary where Caribbean plate moved eastwards
key details of haiti earthquake
- magnitude 7.0
- epicentre = port au prince
- 52 aftershocks all measuring over 4.5
- focus 13km below service
secondary effects of Haiti earthquake
Environmental:
- liquefaction (in Port-au-Prince due to flatlands made of loose sedimentary material) and landslides
- 19 million cubic metres of rubble/debris in Port au Prince, 40-50% of buildings fell in Port-au-Prince – debris, secondary hazards such as landslides: over 30,000
Social:217,000 died, one million homeless, 250,000 residences damaged, 80% of schools in Port-au-Prince and **60% **in South damaged/destroyed, longer term: November 2010 outbreaks of cholera: nearly 6,000 died and over 200,000 infected
Economic: $7.8 billion damage: 120% of Haiti’s GDP at the time, the port was damaged beyond repair: impacting future trade
short term responses to haiti earthquake
- Aid was slow to arrive, due to damage to the port
- USA sent rescue teams and 10,000 troops, as well as $100 million in aid
- 115,000 tents set up and 1 million tarpaulin shelters provided
- Bottled water and purification tablets were provided
- 235,000 people were moved away from Port-au-Prince to less damaged cities
- £20 million donated by the UK government
long term responses to haiti earthquake
- Response was slow, but new homes were built to a higher standard, however over one million still lived in temporary shelters one year after the earthquake
- World Bank waived the countries debt repayments for 5 years
why were impacts of haiti earthquake so bad?
- Shallow depth: seismic waves must travel a smaller distance through the Earth to reach the surface to maintain more energy.
- Struck most densely populated area : - 3 million live in Port au Prince: most in slums after rapid urbanisation
- Poorest country in western hemisphere
- Buildings in Port-Au-Prince poor condition/not designed to earthquake resistant
- Only one airport with one runway and port unusable due to damage: limit aid
- Rescue teams from around the world took 48hrs to arrive due to problems at airport
dates/duration of Tohoku earthquake/tsunami, Japan
- 11th March 2011
- 2:46 pm
- magnitude 9.0
- epth of 20 miles
plates involved in Tohoku earthquake
- destructive
- pacific and north american
- shallow focus, ocean floor shunted vertically about 10m
key stats about Tohoku earthquake
- 16,000 died
- 26,000 injured
- 460,000 homeless
- $360 billion damage
- 1923: last major earthquake
effects of Tohoku earthquake/tsunami
Environmental:
- Landfall: more than 50cm in some beachfront areas
- 25 million tonnes of debris
- shifted earths axis by 10cm
- japans northern coastline moved 2.4m east decreasing effectiveness of tsunami defences
- fires
Social:
- 20,000 dead, 1 million buildings destroyed, 4.4 million households no electricity, 1.5 million no running water
- levels of radiation 8x higher as 7 reactors at Fukushima power station melted down from tsunami
- Secondary (from tsunami):
- 30km around fukishma was evacuated, lack of food/housing where evacuees sent
- Waves up to 40m high: led to damage/pollution up to 6 miles inland
Economic:
- $360 billion by only 6% of GDP
-*costliest natural disaster in the world**
- fishing industry lost $11.3 billion
short term responses to tohuku earthquake
- Japan Meteorological Agency issued tsunami warnings three minutes after the earthquake.
- Scientists had been able to predict where the tsunami would hit after the earthquake using modelling and forecasting technology so that responses could be directed to the appropriate areas.
- 100,000 rescue workers dispatched within hours of tsunami
- government declared a 20 km evacuation zone around the Fukushima nuclear power plant to reduce the threat of radiation exposure to local residents
long term responses to Tohoku earthquake
- April 2011 (one month after), central gov established Reconstruction Policy Council to develop national recovery/reconstruction outlook for tsunami-resilient communities
- Japanese gov approved £190 billion budget spent over 10 years
- Gov coastal protection policy: seawalls/breakwaters ensure performance of a potential tsunami level of up to approx 150 year recurrence interval
why were impacts of tohoku earthquake/tsunami so bad
- Only 45 miles of the coast of Tohoku
- tsunami warnings in coastal areas only followed by 58% who headed for higher ground and the wave hit 49% who did not follow
- sea defences were totally inadequate as nobody expected a 10m tsunami
- Rural areas isolated as Tohoku expressway was damaged
preparation in Japan for tohoku earthquake
- nowhere in the world is better equipped for earthquakes
- like resistant infrastructure that swayed rather than collapsed (tokyo)
- warnings sent out of national tv, radio
- gave time to people who lived on the coast to evacuate
- lots of education in schools
- had lots of time to seek higher ground
- 7.2 quake on 7th march allowed japan meteorlogical agency to send out warnings
- extensive monitoring (as much as there could be)
BUT
- tsunami warnings in coastal areas only followed by 58% who headed for higher ground and the wave hit 49% who did not follow
- sea defences were totally inadequate as nobody expected a 10m tsunami
