StarBulletin.com

Tsunami danger could last for hours


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POSTED: Saturday, February 27, 2010


When the tsunami hits Hawaii, the state's harbors will be especially vulnerable to damages and it could be hours before the state is out of the danger zone, said scientists at the NOAA Pacific Tsunami Warning Center.

The tsunami is traveling toward Hawaii at a speed of about 500 miles per hour, the equivalent of an airliner. The tsunami is now about a half foot high; however, it is expected to reach as high as eight feet when it arrives in Hilo around 11:05 am.

“;Tsunami waves can grow much bigger in shallow water,”; said oceanographer Nathan Becker. “;This is a great concern for Hawaii. It could be a very damaging tsunami.”;

All low-lying coastal areas of Hawaii, especially those near the Hilo, Kahului and Hanalei harbors, will be at risk, Becker said.

“;Eight feet doesn't sound like a lot, but it's very significant when you are close to sea level,”; he said, adding that the tsunami will resemble a flash flood as it descends on the Hawaiian Islands.

Once the first wave hits, damage will be done as it sloshes into land and then back out again, Becker said

“;It does damage both times and picks up debris as it goes,”; he said. “;And, it doesn't necessarily stop with the first wave, often the second or third wave is the largest.”;

When the tsunami reaches Hawaii, the waves will come in like a fast high tide, said geophysicist Barry Hirshorn, adding that the waves will push farther in on the flat lands and that the danger will last for hours.

“;It will be six to 10 hours later for the coast to be all clear,”; Hirshorn said.

According to the latest data, tsunami waves, reaching up to 9 feet, could hit Hilo Bay at 11:05 this morning, according to the NOAA Pacific Tsunami Warning Center.

Waves reaching up to eight feet are expected to hit Kahului by 11:26 a.m., said Delores Clark, a NOAA spokeswoman. The latest estimates, based on wave models, also anticipate three foot wave action in Nawiliwili around 11:42 a.m, Clark said.

By 11:37 a.m., Honolulu residents could see wave action reaching about a foot and a half, she said. While times were not specified, 18 inch waves are expected to hit Haleiwa and waves in Kawaihae could reach about 18 inches.

The waves, while potentially dangerous, will be significantly smaller than the 35 foot waves which hit Hilo in 1960, after a tsunami generated by a 9.8-magnitude earthquake off Chile that killed 61 people in 1960, Clark said. After that tsunami hit, waves in the surrounding area rose as high as 13 feet, she said.

“;People should always be cautious and heed civil defense,”; Clark said. “;Always listen to the local authorities and turn on the radio and TV and listen for updates.”;

That said, it was pandemonium in the Ewa Beach inundation zone, where the warning center is located, this morning. By 3 a.m. lines snaked around the local McDonald's and by 5 a.m. cars were piled up 20 deep in gas station lines. Even before the warning siren sounded, it looked like early morning rush hour on Fort Weaver Road.

If Hilo residents and visitors heed warnings and move inward by a few miles they should be safe, but there will be some damage in the coastal zone, said Victor Sardina, a geophysicist with the Pacific Tsunami Warning Center.

“;You are going to have some run up and some damage in the coastal area,”; Sardina said. “;I hope that nobody stays around the shore. Just move inward.”;

While the tsunami-generated waves aren't expected to reach anywhere near the level that they did in 1960, Sardina said drownings can occur in just a few feet of water and that the currents will be strong.

“;Even a small tsunami, only a few feet tall, can knock a person off their feet,”; Becker said.