SEATTLE - A network of expensive tsunami detection buoys off the West Coast could offer better protection against devastating waves like the one that struck in the Indian Ocean - if they all worked.
Of the six buoys placed throughout the Pacific Ocean, two near Alaska have been broken for 14 months, said Greg Romano, spokesman for the National Weather Service, the branch of the National Oceanic and Atmospheric Administration that maintains the network. One off the coast of Washington broke in November and is now being repaired.
Scientists offer assurances that despite the breakdown they can rely on information gathered by earthquake sensors and tide gauges.
"We are still a fully functional warning system, even without the buoys," Paul Whitmore, chief scientist for the West Coast and Alaska Tsunami Warning Center in Palmer, Alaska, told The Seattle Times. "The impact of those buoys being out is that we have less data upon which to cancel or expand warnings."
The malfunction makes it difficult to see where a wave is headed or how big it will be when it reaches the coast, Whitmore said, which could result in false alarms.
Before the buoys were developed, the nation's 40-year-old tsunami-warning system relied on seismographs to detect and measure earthquakes.
A network of 125 tide gauges scattered from Alaska to California also helped in early detection, but they are widely spaced and aren't an accurate indicator of a wave's size.
"The old system is crude," said Eddie Bernard, director of NOAA's Pacific Marine Environmental Laboratory in Seattle. "You detect a big earthquake, and everybody evacuates."
The newer buoys were added to help reduce the number of costly false alarms, Bernard said.
They have sensors that hang near the ocean floor to detect slight ripples signaling the start of a tsunami. The buoys then transmit warnings via satellite.
In 2003, a magnitude-7.8 earthquake in Alaska triggered a localized tsunami. When the wave reached a nearby buoy, forecasters saw it was too small to be dangerous and canceled the warning.