Scientists defend warning after tsunami non-event

The warning was ominous, its predictions dire: Oceanographers issued a bulletin telling Hawaii and other Pacific islands that a killer wave was heading their way with terrifying force and that "urgent action should be taken to protect lives and property."

But the devastating tidal surge predicted after Chile's magnitude 8.8-earthquake for areas far from the epicentre never materialised and by Sunday, authorities had lifted the warning after waves half the predicted size tickled the shores of Hawaii and tourists once again jammed beaches and restaurants.

Scientists acknowledged they overstated the threat, but defended their actions, saying they took the proper steps and learned the lessons of the 2004 Indonesian tsunami that killed thousands of people who didn't get enough warning.

"It's a key point to remember that we cannot end the warnings. Failure to warn is not an option for us," said Dai Lin Wang, an oceanographer at the Pacific Tsunami Warning Centre in Hawaii.

"We cannot have a situation that we thought was no problem and then it's devastating. That just cannot happen."

Hundreds of thousands of people fled shorelines for higher ground on Saturday in a panic that circled the Pacific Rim after scientists warned 53 nations and territories that a tsunami had been generated by the massive Chilean quake.

It was the largest-scale evacuation in Hawaii in years, if not decades. Emergency sirens blared throughout the day, the Navy moved ships out of Pearl Harbour, and residents hoarded gasoline, food and water in anticipation of a major disaster. Some supermarkets even placed limits on items like Spam because of the panic buying.

At least five people were killed by the tsunami on Robinson Crusoe Island off Chile's coast and huge waves devastated the port city of Talcahuano, near hard-hit Concepcion on Chile's mainland.

But the threat of monster waves that left Hawaii's sun-drenched beaches empty for hours never appeared - a stark contrast to the tidal surge that killed 230,000 people around the Indian Ocean in 2004 and flattened entire communities.

This time, waves of more than 1.5m were reported in Kahului Bay in Maui and in Hilo, on the eastern coast of Hawaii's Big Island, but did little damage. Predictions of wave height in some areas were off by as much as 50%.

In Tonga, where up to 50,000 people fled inland hours ahead of the tsunami, the National Disaster Office had reports of a wave up to 2m hitting a small northern island, with no indications of damage.

And in Japan, where authorities ordered 400,000 people out of coastal communities, the biggest wave was a 4-foot surge that hit the northern island of Hokkaido, flooding some piers.

Still, scientists offered no apologies for the warning and defended their work, all while worrying that the false alarm could lead to complacency among coastal residents - a disastrous possibility in the earthquake-prone Pacific Rim.

A similar quake in Chile in 1960 created a tsunami that killed about 140 people in Japan. The same surge hit Hawaii and devastated downtown Hilo, on the Big Island, killing 61 residents and wiping out more than 500 homes and businesses.