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Last Updated: Thursday, 6 January, 2005, 10:42 GMT
Early warning technology - is it enough?
By Julianna Kettlewell
BBC News science reporter

An early warning bouy, AFP
The Pacific system works in quite a simple way
There is a sense of helplessness and soul-searching after the tsunami last week that killed more than 140,000 people.

Naturally, nations have turned their attention to exploring how such massive loss of life might be prevented in future.

A summit has now decided to create a tsunami early warning system for the Indian Ocean. The high-tech equipment could detect tsunamis that are still many kilometres out at sea.

If disaster strikes twice, it could buy time - enough time, perhaps, to save hundreds of thousands of lives.

But unless you can warn people in remote areas, the technology is useless.

"There's no point in spending all the money on a fancy monitoring and a fancy analysis system unless we can make sure the infrastructure for the broadcast system is there," said Phil McFadden, chief scientist at Geoscience Australia, which has been tasked with designing an Indian Ocean system by the Australian government.

"That's going to require a lot of work. If it's a tsunami, you've got to get it down to the last Joe on the beach. This is the stuff that is really very hard."

Emergency response

The Pacific basin already has a warning system and, when there was a rash of tsunamis in the 60s, it proved invaluable.

The solution need not be high-tech
Professor Bill McGuire
"Although I couldn't put a number on it, a lot of lives have been saved by the Pacific early warning system," Paul Whitmore, of the West Coast and Alaska Tsunami Warning Centre, told the BBC News website.

The Pacific system, which cost tens of millions of dollars to install, works in quite a simple way. A pressure sensor sits on the bottom of the ocean and measures the weight of water above it.

If a tsunami passes overhead the pressure increases and the sensor sends a signal to a buoy sitting on the sea surface.

The buoy then sends a signal to a satellite, which in turn alerts a manned early warning centre.

But, as Dr Whitmore put it: "The warning system is more than just a warning centre. You have to have communication from the centre and then you need some sort of emergency response infrastructure.

"And that is really the hardest part, getting a localised emergency response."

An operator sitting in an early warning centre in Jakarta might know about an impending tsunami, but how does he warn the fisherman in Sumatra, the sweet seller in Sri Lanka, the tribesman on Nicobar island?

In many of these places TV, radio, even a telephone, is not an option.

Therefore, many experts say the biggest challenge is to establish an effective infrastructure, which can reach everybody - no matter how remote.

"The population must be educated about tsunamis and how to respond when it comes," said Professor Bill McGuire, director of the Benfield Hazard Research Centre at University College London.

"It is also critical that the final chain in the communication cascade - from emergency managers to population - is efficient and effective."

Communication failure

Tragically, it seems it was the final chain in the communication cascade that failed on Boxing Day. The truth is people did know about the earthquake, they did know about the tsunami threat, they just didn't know how to tell people.

Girl in southern India
The warning system could save lives, say some experts
The Pacific Tsunami Warning Centre in Hawaii picked up the earthquake. But despite the phone calls they made, the emergency response in Asia did not exist.

Powerful computers in a Vienna office building also picked up the seismic activity. Computers at the Comprehensive Nuclear Test-Ban Treaty (CTBT) Organisation are designed to monitor nuclear explosions anywhere in the world but, as a side-effect, they also detect earthquake vibrations.

Although the organisation's staff were on holiday, the information was automatically sent to several countries including Indonesia and Thailand but, again, the emergency infrastructure was missing.

Nearly everyone agrees an early warning system is needed in the Indian Ocean. Indeed, existing technology - like that used at the CTBT organisation - could play a vital role.

But the hard part will be developing a way of informing every swimmer and every fisherman.

Professor McGuire says that although the response infrastructure does need to be organised, it doesn't need to be complex.

"I think sirens could play an important role," he told BBC News website. "Also, in Bangladesh they have dramatically reduced casualties in cyclones by using officials on bicycles blowing whistles to get people to the cyclone shelters.

"The solution need not be high-tech."

1. Seismic observatories in the region detect an earthquake and send data to the Pacific Tsunami Warning Center in Hawaii.
2. If the earthquake is in the Pacific basin and above 7.5 on Richter scale, an initial "Tsunami watch" alert is sent out.
3. Data from monitoring stations deep on the seabed near the earthquake's epicentre is checked for signs of a tsunami.
4. If a tsunami is detected, full warnings are sent out via national systems which have been set up in several countries.

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