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Indian Ocean tsunami warning

April 11, 2012

A massive earthquake and aftershock off the coast of Sumatra prompted countries from Asia to Africa to issue tsunami alerts. Warnings for several countries have since been lifted.

https://p.dw.com/p/14bSV
A map of Indonesia

The Pacific Tsunami Warning Centre lifted its tsunami warning for all countries located around the Indian Ocean on Wednesday after a tsunami struck Indonesia. The Hawaii-based organization said in a bulletin that "sea level readings now indicate that the threat has diminished or is over for most areas."

India and Sri Lanka also withdrew their tsunami alerts.

"Thankfully, the danger has passed," a scientist at India's tsunami warning center said.

At least three tsunamis with heights of up to 80 centimeters (31inches) hit the coast of Indonesia on Wednesday after an 8.6 magnitude earthquake struck off the coast of Sumatra. The quake and aftershocks prompted widespread panic in Aceh, where people along the coastline fled for higher land.

On alert from Asia to Africa

Tremors were felt as far away as Thailand and southern India. A small tsunami reaching 10 centimeters was recorded on Thailand's Andaman Coast, prompting the authorities to order people to evacuate and close Phuket International Airport until Thursday. India also issued a high-level tsunami warning for its Andaman and Nicobar islands, evacuating vulnerable parts of the islands and initially warning that wave as high as 3.9 meters (around 12 feet) might strike. Warnings for those islands have since been downgraded.

At the peak of the tsunami alert on Wednesday, watches had been activated for Indonesia, India, Sri Lanka, Australia, Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, Tanzania, South Africa and Singapore.

Not a major tsunami

But even then, experts had earlier expressed doubts about a major wave occuring. Professor James Goff, director of the Australia-Pacific Tsunami Research Center at Sydney's University of New South Wales, said the geology of the region could work as a shield, preventing a full-scale tsunami.

"It appears to be a strike-slip fault, which means that it's unlikely to generate a large tsunami," Goff said to Australian news agency AAP.

Kevin McCue, president of the Australian Earthquake Engineering Society, concurred, stating that the damage to Sumatra would be limited.

"The mechanism seems to have been predominantly strike-slip with no substantial vertical displacement of the sea floor, so any tsunami would be small and local," Professor McCue said.

sej/ncy (AP, dpa, AFP, Reuters)