21/01/05

Tsunami early warning system takes shape

Buoys relay information about changes in the sea level to satellites Copyright: NOAA

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The United Nations said last week it would coordinate a tsunami early warning system for the Indian Ocean, due to be operational by 2006, and underlined the importance of not duplicating international efforts.


“We are trying to knock some heads together,” said a spokesperson for UNESCO at the World Conference on Disaster Reduction held last week in Kobe, Japan. “Half a dozen countries and half a dozen international organisations are in danger of doing the same thing.”


An early warning system requires several components. First, earthquakes must be detected. Experts need to then determine whether an earthquake will generate a tsunami and if so, which direction the waves will travel.


Coastal communities in areas that will be hit must be alerted to the danger, for example with a siren or by local broadcast media. These populations need to have been previously trained on what to do when they hear tsunami warnings: where to go and what evacuation routes to take.


Several countries bordering the Indian Ocean have said they will set up national warning systems. While these are effective for local tsunamis, a regional network is necessary in the case of a large ones, such as the one triggered by the earthquake off the coast of Indonesia on 26 December 2004.


For a regional system to work effectively, however, all countries need to exchange information freely. This is where UNESCO steps in.


UNESCO’s Intergovernmental Oceanographic Commission already coordinates the tsunami warning system for the Pacific Ocean and will provide the expertise for its equivalent in the Indian Ocean.


Peter Pissierssens, head of ocean services at the Intergovernmental Oceanographic Commission says that although establishing a full long-term system will take the 18 months announced at the Kobe meeting last week, a short-term solution will be up and running in as few as six months.


This is because there are already sensors and buoys in the Indian Ocean monitoring earthquakes and changes in sea level. These, however, are more suited to monitoring long-term changes in sea level — due to factors such as climate change — than rapid changes due to tsunamis.


Within six months, says Pissierssens, these instruments will be adapted and updated so they can relay information immediately.


He points out that an early warning system, and particularly training populations to evacuate areas at risk, must survive the test of time as tsunamis in the Indian Ocean are rare and the odds of another happening soon are slim.


They are higher, however, in other parts of the world (see ‘Real and serious’ threat of tsunami in Caribbean).


To address this risk, the Intergovernmental Oceanographic Commission is already planning a framework for a global alert system, which will be discussed at its annual meeting later this year.


At the Kobe meeting last week, some participants highlighted the need to create a comprehensive warning system for a range of natural disasters, including many that are more common that tsunamis, such as hurricanes, drought, and plagues of locusts. 


Read more about tsunamis in SciDev.Net’s Tsunami update