THE experience of the Indian Ocean earthquake and tsunami led the Bush administration to announce last week that it would expand the US tsunami warning system within the Pacific Ocean and beyond it, to include the North Atlantic Ocean and the Caribbean Sea.

The US plan proposes that 25 new buoys be added to the six already in the Pacific, and seven new buoys be placed in the North Atlantic and Caribbean, but none in the Indian Ocean.

But last week, Koichiro Matsuura, director-general of UNESCO, said an international tsunami warning network would be created in the Indian Ocean by June 2006, with the expanded US effort completing a global network by 2007. Germany and Japan have offered to help set up the system in the Indian Ocean.

Two of the new US buoys are to float in the seismically active Caribbean Sea, and five above deep ocean waters of the Atlantic. The closest buoy to Bermuda will be some 300 miles to the northwest, and two will lie to the south and southwest of the island, nearer the Bahamas. One will lie a few hundred miles east of Barbados.

The Mid-Ocean News has reported extensively on the views of UK and US scientists who believe that it is appropriate to monitor the danger which may be posed to the island and the entire Atlantic Basin by a potential collapse and tsunami at La Palma in the Canary Islands.

The dramatically enlarged warning system does not extend to seismic monitoring of the flank of the Cumbre Vieja volcano on La Palma, but some warning of any tsunami will be provided by the most easterly buoy, which will lie about midway between Bermuda and the Canaries, south-east of the island and east of the mid-Atlantic Ridge.

The US National Oceanic and Atmospheric Administration (NOAA) announced those plans to expand US tsunami detection and warning capabilities as a contribution to the Global Earth Observation System of Systems, or GEOSS, the international effort to develop a comprehensive, sustained and integrated Earth observation system. The US expansion plan commits a total of $37.5 million over the next two years.

"President Bush is committed to ensuring the safety and protection of US lives and property through a system of monitoring and emergency response that will mitigate the effects of natural disasters, including earthquakes and tsunamis," said John H. Marburger III, science adviser to the President and director of the Office of Science and Technology Policy.

"This plan will enable enhanced monitoring, detection, warning and communications that will protect lives and property in the US and a significant part of the world. Working through GEOSS and other international partners, the US will continue to provide leadership in planning and implementing a global observation system and a global tsunami warning system, which will ultimately include the Indian Ocean."

The additional appropriation will allow NOAA to deploy 32 new advanced technology Deep-ocean Assessment and Reporting of Tsunami, or DART, buoys, and the entire "tsunameter" warning system is expected to be fully-operational by mid-2007. While the US Geological Survey (USGS) does not plan to monitor La Palma in the near future, it will enhance its seismic monitoring and information delivery from the Global Seismic Network, a partnership with the National Science Foundation.

Bermuda will benefit from its geographic proximity to the US: according to NOAA, the new system is expected "to provide the US with nearly 100 per cent detection capability for a US coastal tsunami, allowing response within minutes. The new system will also expand monitoring capabilities throughout the entire Pacific and Caribbean basins, providing tsunami warning for regions bordering half of the world's oceans."

THE New York Times reported that "experts on such systems said that installing the necessary buoys and seabed sensors to detect passing waves or pressure changes would be only the first small step toward averting deaths from future tsunamis".

"Unless you have a good system for spreading an authentic warning and getting a quick response, the technology is not going to help you much," said Dr. George Curtis, described by the Times as a tsunami expert affiliated with the University of Hawaii.

"You have to have your emergency management people ready and the public ready to respond," he said, adding that this would be the biggest challenge in oceans like the Atlantic, where tsunamis are rare.

The Times cited no other expert, but in conversation with the Mid-Ocean News in August last year, Dr. Curtis vehemently objected to the need for any warning system in the Atlantic. He said UK and US scientists calling for a warning system for the Cumbre Vieja volcano were alarmists who were guilty of "shouting 'Fire!' in a crowded theatre", and were also scientifically incompetent.

He did not believe that a landslide could cause an ocean-crossing tsunami, despite considerable evidence to the contrary, including a massive volcanic landslide which happened in Hawaii some 100,000 years ago and left evidence that the resulting tsunami washed coral reefs and submarine debris as high as 1200 feet up the side of Mount Kilauea.

Geophysicist and tsunami expert Steven Ward of the Earth Sciences Department of the University of California at Santa Cruz told the Mid-Ocean News that a DART buoy would not have to be in a direct line between the Canary Islands and Bermuda or the US Eastern Seaboard to give timely warning.

"A good computer model can be scaled to respond to an event, no matter where the buoy is in relation to the event. It's more a question of distance," he said. "I am sure there will be considerable discussion of where they buoys should go before they are actually deployed. I will be a little surprised if the final locations are close to current plans; (deployment) is some time off yet, and they usually set up a committee and look for feedback."

DR. Ward said it would be possible to place one of the DART buoys in a location in the eastern Atlantic which would help warn of any event at the La Palma volcano and of other seismic events in that geographic area.

"You could cover a number of countries in that region," he advised. "An explosion and landslide of the size we modelled at La Palma would make a huge seismic signal. Not only earthquakes are picked up on seismometers. The Mount St. Helen eruption was recorded by seismometers all around the world.

"And remember the Lisbon earthquake (of 1755) happened not that far from La Palma. It could recur before an eruption or landslide at La Palma, and the Cape Verde islands to the south are in a somewhat similar volcanic and seismic situation to La Palma."

Dr. Ward would recommend that the USGS consider seismic monitoring of the Cumbre Vieja volcano, but pointed out that, from the point of view of USGS seismologists and geophysicists, the preference is for a perfectly uniform distribution of stations. "That's the ideal world for seismologists; they want coverage in every direction and distance. That would provide good information about large earthquakes, but we should also be concerned about being able to record (submarine) landslides on the continental shelves. A landslide off the Grand Banks caused a tsunami that killed about 50 people back in 1929."

"La Palma is above water, so it's pretty hard to miss if it goes. I would expect that these new DART buoys would be able to monitor these types of events, as well as earthquakes and tsunami. Landslides make seismic waves that can be recorded, so it would be helpful if the buoys had seismic packages. There may not be a tsunami in the lifetime of the instrument, so you want to make them suitable for as many tasks as possible."

Dr. Ward also saw considerable scientific benefit to the expansion of the tsunami detection system.

"This new effort is focused on the saving of lives and money and property, which is as it should be, but if even the smallest tsunamis are recorded, there's a scientific interest," he said.

"Some of the (computer) models are controversial, and the only way to prove or disprove them is to have more data. So it will be great to have another thirty instruments recording small or lethal tsunamis continuously. They will be an advancement to our scientific understanding."

Dr. Ward said a pressure recording device on the seabed sends a signal every ten seconds to the DART buoy on the ocean surface, and these signals are picked up by a GOES geostationary satellite which relays the signals back to an earth station. "Tsunami waves have a very long wavelength," Dr. Ward advised. "Unlike regular waves, they create a pressure that goes all the way to the sea-floor. So if a tsunami wave goes by, even if its only a few centimetres high, it makes a pressure that can be recorded by pressure gauges placed on the sea-floor, even if they are a few miles down.

"That relatively simple instrument on the sea-floor records the pressure, just like the barometer in your house, and every ten seconds or so, it sends the signal by something like a loudspeaker to the buoy, which records the signal.

"You can't send radio waves through salt water, which is why you need the buoy. The buoy radios the signal to the satellite, which relays it back down to the centre. The buoy is the most difficult part of the system, and the biggest drawback, because a buoy is always subject to storms and collisions and wear and tear."

Dr. Tom Sleeter, Chief Environmental Officer at the Ministry of the Environment, has said that the Government hopes to take part in discussions about geohazard monitoring in the Atlantic, and welcomed the news of the extension of the tsunami detection and warning system to the North Atlantic and the Caribbean.