Indian Ocean (LEDC): Causes And Impact Of An Earthquake And Evaluation Of The Management Response

Question 1

Background of the earthquake

Answer 1

Occurred on Boxing Day, 2004. It was 9.2 on the Richter Scale, the 2nd largest ever recorded.

Question 2

Cause of the earthquake in terms of plates

Answer 2

1. A fault line exists where the Indo-Australian plate is subducted under the Sunda plate
2. A sudden slip of 15 m occurred along a 1600 km section of this fault
3. This lifted the sea floor several metres, triggering a tsunami.

Question 3

Short term impacts on people. [3]

Answer 3

1. At least 125,000 people were injured
2. 1.1 million people were left homeless after the tsunami devastated coastal towns and villages
3. 66% of Sri Lanka’s fishing boats were destroyed.

Question 4

Long term impacts on people [2]

Answer 4

1. 187,000 people were confirmed dead with 43,000 missing
2. 17 low-lying Maldive Islands had their freshwater supplies contaminated by seawater. This made the islands uninhabitable for decades.

Question 5

Short term impact on the environment

Answer 5

A 30 metre high tsunami accumulated from the epicentre to countries all around the Indian Ocean

Question 6

Long term impacts on the environment

Answer 6

1. Damage to coral and mangrove ecosystems on the coast

2. Worldwide rise in sea level of 0.1 mm as water spilled out from the Indian Ocean after its seafloor was raised.

Question 7

Describe the management response in terms of prediction and precautions. [2]

Answer 7

1. No official warning system was in place.
2. A 10 year old British girl on holiday in Phuket, Thailand observed the water receding and warned her parents. The beach was subsequently evacuated, saving about 100 lives.

Question 8

Describe the immediate responses to the earthquake. [2]

Answer 8

1. International aid and expertise from around the world, including over $7 billion US
2. A state of emergency was declared in Sri Lanka, Indonesia and the Maldives to allow orderly distribution of aid.

Question 9

Describe the long term strategy put in place after the earthquake.

Answer 9

The Indian Ocean Tsunami Warning System was set up by UNESCO.
This included 25 new seismographic stations to detect future tsunamis and provide warnings to countries in the region.