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Indian Ocean Tsunami Timeline

(December 26, 2004)

The Indian Ocean Tsunami of 2004 was triggered by a massive undersea earthquake off the coast of Sumatra, Indonesia. It generated devastating waves that struck coastal areas across South and Southeast Asia and East Africa, killing over 227,000 people and prompting major improvements in global tsunami warning systems. More Less

Go to: Timeline | Event List | Key Facts | Directory

The Earthquake

2002 Sumatra earthquake as foreshock

Nov 2, 2002

The 2002 Sumatra earthquake is believed to have been a foreshock, preceding the main 2004 Indian Ocean earthquake by over two years.

Image source: 2004 Indian Ocean earthquake and tsunami

2002 Sumatra earthquake as foreshock

Magnitude 8.1 quake near Auckland Islands

Dec 23, 2004

The 2004 Indian Ocean earthquake came just three days after a magnitude 8.1 earthquake in the sub-antarctic Auckland Islands, an uninhabited region southwest of New Zealand, and Macquarie Island to Australia's south.

Mw 9.2–9.3 earthquake strikes off Aceh

Dec 26, 2004

On 26 December 2004, at 07:58:53 local time (UTC+7), a Mw 9.2–9.3 earthquake struck with its epicenter off the west coast of Aceh, in northern Sumatra, Indonesia. It was initially documented as having a moment magnitude of 8.8.

Seafloor rise displaces 30 km3 of water

Dec 26, 2004

As well as sideways movement between the plates, the earthquake resulted in a rise of the seafloor by several metres, displacing an estimated 30 km3 (7.2 cu mi) of water and triggering devastating tsunami waves.

Earth's oscillation still detectable by February 2005

Feb 1, 2005

By February 2005, the earthquake's effects were still detectable as a 20 μm complex harmonic oscillation of the Earth's surface, which gradually diminished and merged with the incessant free oscillation of the Earth more than four months after the earthquake.

Magnitude 8.6 Nias–Simeulue earthquake

Mar 28, 2005

The magnitude 8.6 2005 Nias–Simeulue earthquake originated off the coast of the Sumatran island of Nias. It is not considered an aftershock despite its proximity to the epicentre, and was most likely triggered by stress changes associated with the 2004 event.

Image source: 2005 Nias–Simeulue earthquake

Magnitude 8.6 Nias–Simeulue earthquake

2021 study revises magnitude to Mw 9.2

Jan 1, 2021

A 2016 study estimated the magnitude to be Mw 9.25, while a 2021 study revised its 2007 estimate of Mw 9.1 to a new magnitude of Mw 9.2.

Tsunami Impact

Deadliest tsunami in history begins

Dec 26, 2004

The resulting tsunami became the deadliest tsunami in history, the deadliest natural disaster of the 21st century, and one of the deadliest natural disasters in recorded history.

First wave hits five minutes after mainshock

Dec 26, 2004

The first wave came five minutes after the mainshock with a marginal drop in sea level. The tsunami moved counter-clockwise around Phuket Island, as was the case at Okushiri Island in the 1993 Hokkaido earthquake.

Magnitude 8.7 quake without major tsunami

Mar 28, 2005

Not every earthquake produces large tsunamis: on 28 March 2005, a magnitude 8.7 earthquake hit roughly the same area of the Indian Ocean but did not result in a major tsunami.

Humanitarian Response

Worldwide humanitarian response raises $14 billion

Dec 26, 2004

The plight of the affected people and countries prompted a worldwide humanitarian response, with donations totaling more than US$14 billion (equivalent to US$24 billion in 2025 currency).

GAM declares cease-fire on 28 December

Dec 28, 2004

The widespread devastation caused by the tsunami led GAM to declare a cease-fire on 28 December 2004, followed by the Indonesian government, and the two groups resumed long-stalled peace talks.

Terra Research warns India of possible shift

Dec 30, 2004

On 30 December 2004, four days after the tsunami, Terra Research notified the India government that its sensors indicated a possibility of a 7.9 to 8.1 magnitude tectonic shift in the next 12 hours between Sumatra and New Zealand.

UNEP mobilizes $9.3 million for recovery

Jan 1, 2005 - Dec 31, 2007

UNEP established an emergency fund, set up a Task Force to respond to requests for assistance from countries affected by the tsunami, and was able to mobilize and distribute approximately US$9.3 million for environmental recovery and disaster risk reduction between 2004 and 2007.

Aceh peace agreement signed

Aug 15, 2005

Following the cease-fire declared after the tsunami, the Indonesian government and GAM resumed long-stalled peace talks, which resulted in a peace agreement signed 15 August 2005.

Aid workers executed in north-east Sri Lanka

Aug 1, 2006

In August 2006, fifteen local aid staff working on post-tsunami rebuilding were found executed in north-east Sri Lanka after heavy fighting between government troops and the Tamil Tiger rebels, the main umbrella body for aid agencies in the country said.

Aftermath and Recovery

Piracy incidents drop 71.6% after tsunami

Jan 1, 2005 - Dec 31, 2005

Due to multiple factors, there was a 71.6% drop in the number of piracy incidents between 2004 and 2005, from 60 to 17 incidents.

Smith Dharmasaroja assigned Thai warning system

Jan 1, 2005

Smith Dharmasaroja, a meteorologist who had predicted that an earthquake and tsunami 'is going to occur for sure' in 1994, was assigned the development of the Thai tsunami warning system.

Indian Ocean Tsunami Warning System formed

Jan 1, 2005

The Indian Ocean Tsunami Warning System was formed in early 2005 to provide an early warning of tsunamis for inhabitants around the Indian Ocean coasts.

Image source: Tsunami warning system

Indian Ocean Tsunami Warning System formed

HMS Scott surveys seabed around quake zone

Feb 1, 2005 - Feb 28, 2005

In February 2005, the Royal Navy vessel HMS Scott surveyed the seabed around the earthquake zone, which varies in depth between 1,000 and 5,000 m (550 and 2,730 fathoms; 3,300 and 16,400 ft).

Evidence of ancient tsunamis found at Phra Thong

Jan 1, 2008

In 2008, a team of scientists working on Phra Thong, a barrier island along the hard-hit west coast of Thailand, reported evidence of at least three previous major tsunamis in the preceding 2,800 years, the most recent from about 700 years ago.

Ancient tsunami evidence found in Aceh

Jan 1, 2008

A second team found similar evidence of previous tsunamis in Aceh; radiocarbon dating of bark fragments in the soil below the second sand layer led scientists to estimate that the most recent predecessor to the 2004 tsunami probably occurred centuries earlier.

Film On the Island depicts tsunami rescue

Jan 1, 2012

On the Island (2012) features two people stranded on a Maldives uninhabited island who are rescued because of the tsunami.

Image source: Island

Film On the Island depicts tsunami rescue

Piracy incidents exceed pre-tsunami levels

Jan 1, 2013 - Dec 31, 2014

However, between 2013 and 2014, piracy incidents rose dramatically by 73.2% to exceed pre-tsunami levels.

Indian Ocean Tsunami Archives join UNESCO register

Jan 1, 2017

The Indian Ocean Tsunami Archives were added to the UNESCO Memory of the World register in 2017.

Image source: Memory of the World Programme

Indian Ocean Tsunami Archives join UNESCO register

Key Facts

  1. A magnitude 9.1–9.3 earthquake struck off the west coast of northern Sumatra, Indonesia, on December 26, 2004.
  2. The earthquake was one of the most powerful ever recorded and lasted approximately 8 to 10 minutes.
  3. Tsunami waves reached heights of up to 30 meters (100 feet) in some areas, devastating coastlines in Indonesia, Thailand, Sri Lanka, India, and beyond.
  4. The disaster killed an estimated 227,000 people across 14 countries, making it one of the deadliest natural disasters in recorded history.
  5. In response to the tragedy, the Indian Ocean Tsunami Warning System was established and became operational in 2006.

Source

This Indian Ocean Tsunami timeline was generated with the help of AI, using information found on the internet.

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