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02 August 2011

INDONESIA: Evacuation towers for tsunami escape route

Photo: Natalie Bailey/IRIN Are buildings like these the answer?

WEST JAVA, 2 August 2011 (IRIN) - City officials in Padang have come up with an unusual strategy to save the lives of its citizens in the event of a tsunami: multi-storey buildings.

The city on the west coast of Sumatra Island is in one of Indonesia's most quake-prone regions, where a 7.6 magnitude quake in 2009 killed more than 1,000 people and destroyed large parts of the city.

"If we try to build just horizontal evacuation roads, they won't be enough. But multi-storey buildings are one way to save the people," Dedi Henidal, director of Padang's Natural Disaster Mitigation Board, told IRIN.

Hundreds of thousands would be killed if Padang were hit by a large tsunami and there were no evacuation towers, say disaster management experts.

"How many people would die if a tsunami were to occur today? 400,000," says Sutopo Purwo Nugroho, head of the Centre for Data, Information and Public Relations at the National Agency for Disaster Management in Jakarta, referring to a quake of magnitude nine or above on the Richter scale.

Another tsunami disaster model, done by his centre earlier this year, estimated that up to 650,000 people could die if Padang were hit by a massive tsunami.

However, according to Nugroho, it is not a matter of if the west coast of Sumatra could be struck by another massive quake, but when.

"Tsunamis have been generated in this region approximately every 200 years. Data was found back to 1350, with the last super cycle being in 1797 and 1833, indicating that a tsunami is due in Padang."

Coral reefs in West Sumatra have been studied by Indonesian scientists in much the same way as tree trunks to provide a biological history map of when the reefs were struck by quakes and tsunamis, says Nugroho.

Sumatra's north coast was devastated by a tsunami in December 2004, when a 9.1 magnitude quake struck, killing more than 180,000 people in Indonesia and 230,000 across the region.

Escape routes

To date, Padang and coastal villages along West Sumatra have built several pedestrian evacuation routes. But the region's size, plus its location on a narrow strip of land, rimmed by rivers and mountains, means that even if it built dozens more, residents could not escape in 25 minutes or less, the estimated warning time between an earthquake and when a tsunami would strike the coast, says Nugroho.

It is a lesson that Padang learnt in 2009 when a relatively moderate quake struck off Sumatra's west coast. "We learnt lessons not only for the city, but at the provincial level," says Henidal.

Since 2010, Padang has built 14 multi-storey buildings with assistance from local businesses, such as broadcasting company TV1, and the Japan International Cooperation Agency (JICA), says Henidal.

The escape towers have been designed with civil engineers from the University of Kyoto, specializing in quake-resistant buildings, as well as Indonesian geophysicists and seismologists, says Henidal. His agency is running tests to check whether the buildings can withstand quakes stronger than magnitude nine.

Disaster management experts in Jakarta say the success of these evacuation points depends on whether Padang's Disaster Mitigation Board builds according to the specifications developed by the national technical experts.

"The important thing in my opinion is whether these buildings are being built to withstand the highest scale of earthquake that can occur in Padang or West Sumatra," says Suhardjono, director of the Earthquake and Tsunami Center in Indonesia's Meteorology, Climatology and Geophysics Board, who like many Indonesians goes by only one name.

The city plans to build almost 100, with each building providing an escape for between 3,000 to 6,000 people, as part of its overall disaster strategy for the city, added Henidal.

The escape towers, built with both public and private funding, will also be used for other purposes, such as high schools, or offices.

However, Nugroho said the evacuation towers should not just save lives in the short term, but also become long-term life-saving centres, stocking food, medicines and tents.