CS - Asian Tsunami 2004 - Hazardous Earth

When?

26th December 2004 at 7:56am

Where?

North-west coast of Sumatra

What caused it?

Subduction of the Indo-Australian plate under the Eurasian plate along a fault 1200km long.

10-20m of vertical motion

What was it?

A 4 minute earthquake

Magnitude 9.0 on Richter scale

Epicentre only 150km from land

Focus only 30km deep

What factors contributed to the high vulnerability and impacts in the area?

• Tsunamis uncommon in Indian ocean, so coastal communities in countries such as Indonesia and Sri Lanka were unaware of the dangers posed by tsunamis, so unprepared

• Most of the island chains in the Indian ocean, e.g. the Maldives, are flat and low-lying. Many of the coastlines also tend to be flat/very gentle slope.

  • Fishing villages + tourist towns built right up to the water’s edge to make max use of the magnificient beaches.

  • So, the tsunami rolled well inland with little to no resistance, and picking up debris and heavy objects along the way

• Much of Indian ocean densely populated. Thriving fishing communities and tourism has flourished = large numbers of people at risk

• Many of countries affected, e.g. Indonesia and Sri Lanka, are extremely poor. Did not have the necessary emergency supplies, procedures, and infrastructure to cope with this disaster so needed heavy foreign assistance

• No early warning system for the Indian ocean. Only Thailand had a warning system, which failed. This is bc of the infrequency of tsunamis in the area. 10,000s people could have been saved.

  • The Pacific Tsunami Warning Center in Hawaii picked up on the earthquake but did not have the necessary contacts to alert officials in Thailand

  • There was a 2 hour delay between the wave hitting Sumatra then Thailand

• Time: the focus was shallow, and the epicentre close to the coastline.

  • There were only 15 minutes between the earthquake and the tsunami hitting Aceh

Draw a map of the location of the earthquake

What happened in Sumatra (Indonesia)

• Northern province of Aceh was closest to the epicentre and was worst affected.

• Waves up to 12m travelled 2km onshore

• At least 100,000 killed

• 80% of the province was destroyed

What happened in Sri Lanka?

• ~28,000 killed

• Mostly dead on Eastern seaboard

What happened in India?

• Worst hit area was the remote coastline in the Southern province of Tamil Nadu

• Hit by 10m high waves

• 15,000 people killed

What happened in Thailand

• Southern Thailand holiday beaches devastated

• Majority of the 7,000 deaths were among foreign tourists

Andaman and Nicobar Islands

Unknown numbers of people - possibly more than 30,000 killed

Survivors left without food and battling crocodiles washed onshore by the tsunamis

What happened in the Maldives

Only 67 deaths confirmed, and 68 of the 87 tourist resorts remained open

Sri Lanka absorbed most of the energy

The Maldives’ atolls are on top of 3000m tall, practically vertical underwater mountains, so all that was felt at the surface was a ripple compared to what could have been.