This year commemorations for World Tsunami Awareness Day (WTAD) aim to honour the memory of the 2004 Indian Ocean Tsunami on its 20th anniversary, to highlight its lessons for children and youth around the world and to celebrate the success of progress made in advancing early warning system coverage. Empowering them with this knowledge, which is captured in the #GetToHighGround campaign, can be the difference between life and death when tsunamis emerge.

What happened

The morning of December 26, 2004 saw the worst disaster in Indonesia’s history. A magnitude (M) 9.1 submarine earthquake occurred along the Indian Ocean subduction zone triggering a massive tsunami that destroyed 800 km of the coastal areas of Aceh Province with inundation observed as far as 6 km inland. It was the first global disaster of the 21st century and remains one of the deadliest disasters in recent human history. 

This animation demonstrates the significance of the south-to-north rupture in understanding the behavior of this tsunami

Once generated, the tsunami radiated outward in all directions, striking the coasts of Indonesia and India's Andaman and Nicobar Islands within 20 minutes of the earthquake and the northeastern coast of Somalia in Africa seven hours later.

In Indonesia's Aceh province in Northern Sumatra, waves reached 167 feet (51 meters) and caused flooding up to three miles (five kilometers) inland.

On the other side of the ocean, in Somalia, waves ranged in height from 11 to 31 feet (3.4 to 9.4 meters). The tsunami was also observed on over 100 coastal water-level stations in the Atlantic and Pacific Oceans, making it a global tsunami.

Key statistics

Shipwreck in an ocean
  • Post disaster damage and loss assessment revealed staggering numbers on the calamity that include over 220,000 human fatalities and the destruction of 139,000 houses, 73,869 hectares of agricultural lands, 2,618 kilometers of roads, 3,415 schools, 104,500 small-medium enterprises, 13,828 fishing boats, 119 bridges, 669 government buildings, 517 health facilities, 1,089 worship places, 22 seaports, and 8 airports and airstrips.
  • The tsunami took a terrible toll on young lives, killing over a third of children under age seven in heavily damaged communities.
  • Of the 30,000 people killed by the tsunamis in Sri Lanka, at least 10,000 were children.
  • Adult women were twice as likely to die as adult men, and that in Aceh and North Sumatra, physiological differences between adult men and women were a contributing factor in mortality.
  • The ability to self-evacuate through learned skills such as climbing and swimming influenced high mortality rates among women.
  • Women’s ability to safely access shelters were affected by clothing that restricted their movements, the higher likelihood that women were evacuating with children and elderly, and differences in knowledge and shelter safety conditions, affecting women’s ability to safely access these shelters
  • Why did the Indian Ocean Tsunami kill so many compared to other earthquakes of similar size? First, the earthquake occurred just offshore of a major population centre.
  • It is important to bear in mind that over 70% of the Indian Ocean Tsunami fatalities, 167 000 or more, were killed by the local tsunami that arrived on the shores of Sumatra within minutes after the earthquake rupture.
  • The quake ruptured the greatest fault length of any recorded, spanning a distance of an estimated 1,500km (900 miles) - longer than the US state of California.
  • The length of the rupture meant that the waves reached a wider geographical area - as far afield as Mexico, Chile, and the Arctic.
  • The waves travelled at speeds of up to 800km/h (500mph)
  • The reconstruction costs were estimated to be US $4.9 billion while committed funds from various sources including the international community donors and the Government of Indonesia amounted to US$ 6.7 billion (BRR, 2009).

Faces of the Tsunami: Survivors

When a tsunami struck, this girl's risk education saved more than 100 lives.

Two weeks before the tsunami, Tilly Smith had learned about the warning signs of a tsunami in her geography class. She noticed the strange waves and immediately alerted her family. Despite initial doubt, her dad listened and convinced a security guard to evacuate the beach. Thanks to Tilly's awareness, over 100 people made it to higher ground, escaping the deadly waves.

Mak lang survived the 2004 Indian Ocean Tsunami in Malaysia.

Maria Matang from Thailand survived the 2004 Indian Ocean Tsunami.

Tomas Alvarez Belon's survived the Indian Ocean Tsunami while in Thailand.

Lessons learned and future preparedness

speakers

The people who lived through this tragedy have been forever changed by it. Its lessons, including the warning signs of a tsunami and the importance of seeking high ground, have been engraved in their memories. However, in the 20 years since the disaster, a new generation - that was too young or was born after the disaster - can stand to benefit from the lessons that have been internalized by older survivors. 

On Simeulue Island, Indonesia communities use the knowledge of “Smong”, developed following the 1907 tsunami

Before embarking on a painstaking reconstruction effort, the Government of Indonesia created a “Master Plan for the Rehabilitation and Reconstruction of Aceh and Nias, North Sumatra”. Parallel to this effort, the government also established the Agency for the Rehabilitation and Reconstruction of Aceh and Nias (BRR), an ad-hoc agency, first of its kind, mandated to implement and coordinate government-funded projects and coordinate donor- and NGO- funded projects from April 2005 to April 2009. The “Build Back Better” philosophy was adopted in the reconstruction effort. This guiding principle seeks to ensure that every reconstruction effort shall integrate the concept of Disaster Risk Reduction that would help reduce future disaster risk and build resilience. By the end of the project period, BRR had implemented and coordinated a total of roughly 12,000 projects.

Post-tsunami recovery and reconstruction efforts generally resulted in significant achievements in terms of housing, infrastructure, environment, agriculture, livelihood, health, local economy, education, and disaster management sectors. The enactment of Law of the Republic of Indonesia Number 24/ 2007 concerning Disaster Management and the subsequent transformation of disaster management entities marked a major shift in disaster management paradigm in Indonesia which should help prepare Indonesia in responding more effectively to future disaster events.

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