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Is the Indian Ocean Ready for Another Mega-Tsunami?

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Is the Indian Ocean Ready for Another Mega-Tsunami?

The 2004 Indian Ocean Tsunami sparked the world’s largest humanitarian and disaster recovery effort. But 20 years on, governments still fail to sufficiently integrate disaster reduction into longer-term strategic thinking.

Is the Indian Ocean Ready for Another Mega-Tsunami?

In this photo taken on Jan. 2, 2005, a village near the coast of Sumatra lay in ruins after the 2004 Indian Ocean Tsunami.

Credit: U.S. Navy photo by Photographer’s Mate 2nd Class Philip A. McDaniel

This year marks the 20th anniversary of the devastating 2004 Indian Ocean Tsunami. Commemorations are taking place around the region for the estimated 230,000 lives lost in 14 countries affected by the disaster. It saw the largest recorded humanitarian response, mobilizing support from local and international responders. 

The tsunami’s destruction focused the world’s attention on the need for sustained action in disaster risk reduction. Since then, progress has been made, but efforts are waning and in some measures are backsliding amid short-termism and an inability to sufficiently integrate disaster reduction into longer-term strategic thinking at the national level.

We need to find the momentum we had after the 2004 tsunami to deliver disaster reduction in the region. 

The 2004 Tsunami

On the morning of December 26, 2004 a devastating 9.2 magnitude earthquake occurred 160 kilometers off the coast of North Sumatra, Indonesia at a depth of 30 kilometers. This came after decades of tension released along the Burma and Indo-Australian tectonic plates and caused a large earthquake in two phases. These lasted several minutes over an estimated 1,600 km of fault surface. The seabed rose by several meters over hundreds of kilometers, pushing an estimated 30 cubic meters of water above sea level and triggering a tsunami. 

The waves were observed as far away as Mexico, Chile, and the Arctic Circle. 

As the wave approached shallower waters, it slowed down, causing its size to increase to an estimated 30 meters high and 200 kilometers wide. It reached Indonesia’s Aceh province 20 minutes after the earthquake, hitting the coastal city of Meulaboh. The wave crashed into the coastline and killed 10,000 residents and destroyed 80 percent of its buildings. It then reached Banda Aceh, home to 250,000 people, where outlying islands caused the tsunami to intensify. Waves of 20 to 35 meters high hit the coastal city and reached 3.5 kilometers inland. The waters reached the second floor of many buildings and claimed an estimated 168,000 lives.

As the wave progressed, it impacted India’s Andaman and Nicobar Islands. Eyewitnesses recounted that they heard cracking and rumbling sounds that came from underwater landslides. Massive undersea landslides triggered by the earthquake saw the formation of waves of up to 15 meters high. As the islands are flat, the tsunami waves had significant impact. Luckily, local communities had an oral tradition that passed down knowledge of previous earthquakes and tsunamis; many in the islands’ community listened to the warning signs and evacuated to higher ground. 

However, the Indian Air Force base located along the coast on Car Nicobar was inundated by the tsunami waves, with residential buildings and its hospital reduced almost to rubble. Four oil tankers nearby were displaced 800 meters from the seashore to the air force base’s main gate.

As the tsunami wave continued, it reached Thailand’s Phang Nga and Phuket provinces an hour and a half after the earthquake. It claimed the lives of around 5,400 people, including 2,000 foreign tourists. An estimated 2,500 to 3,000 irregular migrant workers from Myanmar also lost their lives in Thailand. With Aceh bearing the main brunt of the tsunami, the waves that reached the northwestern states of Peninsula Malaysia were likely reflected rather than direct. Still, 52 people died and property damage resulted in thousands of displaced people.   

Mainland India, the Maldives, Myanmar, and Sri Lanka were next affected by the tsunami. India lost 10,800 people. Sri Lanka suffered the second highest casualty rate, with over 35,000 people lost. The Maldives had graduated from the United Nations’ “least developed” category four days before the tsunami. The then-Maldives president, Maumoon Abdul Gayoom, said that “nearly two decades of development were washed away” in the tsunami. 

The tsunami waves hit countries as far away as the east coast of Africa, including South Africa, Seychelles, Somalia, Tanzania, and Kenya.