Boxing day Tsunami

Question 1

Facts:

Answer 1

• 26th December 2004
• 9.1 magnitude earthquake - 3rd largest earthquake ever (2.5 times smaller than the largest earthquake ever recorded)
• The tsunami reached speeds of up to 500 kph
• Focus 30 km deep

Question 2

Causes:

Answer 2

• 9.1 magnitude earthquake triggered a tsunami which was responsible for the largest loss of life of any tectonic event since records began
• The Australian plate is subducted under the Eurasian plate and a 15-20 m slip occurred along the 1600 m fault line twice over 4 minutes at 7:58am
• The 4 minute slip was the longest ever recorded rupture since records began
• The epicentre was 160 km offshore in the Indian Ocean, north of Simeulue Island off the western coast of northern Sumatra and the focus was 30 km below sea level
• The uplift of the sea floor by several meters displaced several billon tonnes of seawater and reached the Sumatran shore with a 20 meter wave
• The maximum height the wave reached was 30 m
• The earthquake was on a thrust fault
• The wave reached areas as far away as South Africa which incurred a wave of 1.5 m in height 16 hours after the earthquake
• The 2002 Sumatra earthquake was believed to be a foreshock of a magnitude of 7.3 which was 61 times smaller than the 2004 earthquake
• Convection currents in the mantle were forcing the Australian plate to subduct under the Eurasian plate where pressure has built up over time until the plate slipped releasing a significant amount of energy equalling 4.4 trillion Joules of energy which displaced the water which caused the tsunami and caused devastation to south asia and other surrounding area around the Indian Ocean.

Question 3

Social Impacts:

Answer 3

• The most destructive tectonic event since 1990
• The tsunami killed 250,000 in 14 different countries
• Highest death toll was on the Indonesian island of Sumatra where 130,000 were killed and over 30,000 remain missing
• In Sumatra 500,000 people were made homeless and over 80,000 homes were destroyed along with damage to ports, boats, roads, bridges, hospitals and crop fields within 1 km of the shore
• The tsunami reached as far away as South Africa where 8 people were killed - this is over 8000 km away from the epicentre
• In Sri Lanka a train derailed by the force of the wave killing over 1000 people
• Loss of up to 9,000 tourists in what was the peak holiday travel season
• The earthquake still caused a large amount of damage despite it being 240km off the coast - this was mainly due to poorly built homes
• Outbreak of waterborne diseases such as Cholera and dysentery spread due to the lack of clean water and sanitation in the refugee camps killing at least 150,000
• Emotional and psychological impacts on the survivors and aid workers was great

Question 4

Economic Impacts:

Answer 4

• Incomes were lost due to damage to the ocean floor and fishing boats which was the primary industry
• Loss of tourism heavily affected Thailand and the Maldives
• Local economies were devastated, the overall impact to the national economies was minor as they are a relatively small percentage of the GDP
• 66% of fishing boats and industrial infrastructure were destroyed - 51,000 boats lost in Sri Lanka - this led to the fibreglass industry booming due to high demand for boats, but this led to a lower quality of boats

Question 5

Long term responses:

Answer 5

• The Indonesian government relocated people from the refugee camps into new homes - however the building of these took a much greater time than expected due to the lack of building materials and destruction to main transport links
• A tsunami early warning system was put in place in the Indian Ocean at a cost of $20 million
• Tsunami education has now improved a large amount since the 2004 event where people in the Indian ocean now know to get to high land in the event of a tsunami

Question 6

Environmental

Answer 6

-Land disputes broke out as documentation was lost and in some cases land was lost by the erosion from the tsunami

Short term responses:

• Bodies were buried in mass graves to prevent the spread of disease
• Over $7bn was provided by governments and NGO’s in aid to help with reconstruction
• 5 million people had to be relocated into temporary refugee camps in the need of shelter, food and water
• It took months to clear debris before rebuilding could start again
• The delivery of relief and aid was reduced as parts of Strait where water depths were previously 4,000 ft are now only 100 ft making shipping impossible and dangerous and relied was much more challenging