After the tsunami in the Indian Ocean caught so many people unaware, U.S. officials said the West Coast wasn't as likely to be slammed without warning, thanks to a sophisticated tsunami-detection system in the Pacific Ocean.

But three of the six buoys that are the system's high-tech centerpiece have been out of commission for months or longer — including the one off the coast of Washington.

Scientists still can warn of possible tsunamis by relying on information from lower-tech earthquake sensors and tide gauges. But the blind spots in the buoy data make it harder to tell where the waves are headed and how big they will be when they reach the coast, said Paul Whitmore, chief scientist for the West Coast and Alaska Tsunami Warning Center in Palmer, Alaska.

"We are still a fully functional warning system, even without the buoys," Whitmore said of the warning center, which is part of the National Weather Service. "The impact of those buoys being out is that we have less data upon which to cancel or expand warnings."

That means a higher chance of false alarms, because forecasters always will err on the side of caution when they detect an earthquake that might trigger deadly waves.

"If we see a big coastal earthquake ... that we suspect could cause a tsunami, we will issue a warning right away — a full-scale, get-out-of-Dodge warning," Whitmore said.

U.S. Rep. Jay Inslee, D-Bainbridge Island, said the breakdowns underscore the need for an expanded network.

"We need to add additional buoys, both for our own protection and to add redundancy in case these things go down," he said. "The world needs a warning system, too."

Inslee said he will co-sponsor bipartisan legislation for a $30 million global-warning system with 50 new buoys and other instruments. A dozen or more of the buoys would be deployed in the Pacific.

A similar Senate bill has been proposed by Sen. Joe Lieberman, D-Conn. Australia, Germany and other nations also have offered to help build and maintain a warning system in the Indian Ocean.

Sen. Dianne Feinstein, D-Calif., has asked the Government Accountability Office, Congress' investigative arm, to determine whether the tsunami-warning system in the Pacific is adequate.

When the network of warning buoys was developed over the past several years, scientists said six instruments were the bare minimum needed to cover the vast Pacific Ocean. With sensors that dangle near the ocean floor, the buoys can detect the tiny ripples that signal the start of a tsunami. They automatically transmit warnings via satellite.

Of the three buoys deployed across the north Pacific near Alaska, two 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.

GREG GILBERT / THE SEATTLE TIMES This device is placed on the ocean floor to detect tsunami activity. It signals the buoy above the surface, and warnings are automatically transmitted via satellite.

The buoy off Washington's coast stopped working in November and is being repaired. It will be returned to its station soon, Romano said.

The others probably won't be fixed until spring because of bad weather.

He blames the problems on harsh conditions in the open ocean and the relatively new designs of the instruments, which are being fine-tuned.

Before the buoys were developed, the nation's 40-year-old tsunami-warning system relied on two elements: seismographs to detect and measure earthquakes and 125 tide gauges scattered from Alaska to California to detect the first swells from a tsunami as they reach shore near the epicenter of the quake.

"We really don't know for certain a tsunami has been generated until we see the tide gauges," Whitmore said.

But the tide gauges are widely spaced and aren't always an accurate indicator of the size of the wave, because they can be confounded when water sloshes around in a bay.

The buoys were added to the system primarily as a way to reduce the number of costly false alarms, said Eddie Bernard, director of the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle.

Christian Meinig, lead development engineer with the National Oceanic and Atmospheric Administration, examines a device that detects tsunami activity.

"The old system is crude," he said. "You detect a big earthquake, and everybody evacuates." The estimated price tag for a needless evacuation in Hawaii in 1994 was $40 million in lost productivity.

The buoys are able to provide better data on the size and direction of the waves, but their usefulness is limited by the small number deployed, Bernard said.

In 2003, a magnitude-7.8 earthquake in Alaska triggered a localized tsunami. But when the wave reached a nearby buoy, forecasters could see it was too small to be any danger to Hawaii or the West Coast, and they canceled the warning.

The success story owed a lot to luck, however.

"The earthquake happened at exactly the right location, and our instrument picked it up very quickly," Bernard said. "We don't have enough coverage to have that same level of quickness for the entire Alaskan archipelago."

An ideal system throughout the Pacific would include about 21 buoys. Each one costs about $250,000 to build and thousands of dollars a year to operate and maintain — as the recent malfunctions prove.

Some experts are wary of overreliance on technology in a worldwide warning system. Simple education programs might prove as effective in saving lives by teaching people what signs to watch for and when to run for higher ground, said Brian Atwater, an expert on tsunamis and earthquakes who is a U.S. Geological Survey researcher at the University of Washington.

And technology is worthless without systems to disseminate warnings and a sustained investment to maintain the network, said Michael Glantz, senior scientist at the National Center For Atmospheric Research, based in Colorado.

"These systems are hard to keep going for events that are as rare as big tsunamis," he said.

For people who live on the West Coast, the warning system also has some fundamental limitations. It would offer some measure of protection against tsunamis triggered by distant earthquakes — say in Alaska or Chile — that would take several hours to reach Washington or Oregon.

But it would be little help in the case of a massive earthquake directly off the coast, which could send killer waves crashing ashore in as few as 30 minutes.

"Never underestimate the value of knowing what to do when the world starts shaking around you," Bernard said.

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com