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Saturday, March 31, 2001



[ TSUNAMI PREPAREDNESS /
55TH ANNIVERSARY OF 1946 HILO WAVE ]




COURTESY OF NOAA
A man is pointed out in this historic photograph of the April 1, 1946,
tsunami and flooding of Hilo. After striking Hawaii, the tidal wave
struck the Marquesas Islands and Antarctica.



Officials betting
on tsunami

The Hawaiian Islands are
playing on house money over
tsunami threat

>> Technology to improve tsunami alert


By Helen Altonn
Star-Bulletin

A GIANT TSUNAMI similar to the one that killed 159 people in Hawaii on April 1, 1946, could slam the islands at any time, emergency officials warn.

"Since 1900 we've had, on an average, a destructive or killer tsunami about every 12 or 14 years, and now it's been over 35 years since we've had one," says Joe Reed, Oahu Civil Defense Agency administrator. "It's way overdue."

Many advances have occurred in recent years in the Pacific Tsunami Warning System and in research to understand and better predict a devastating tsunami.

Civil Defense has a good array of sirens that cover most populated coastal areas that would be affected, Reed said.

But none of that will matter if people do not understand how dangerous a tsunami can be and take warnings seriously.

Those in the Civil Defense network are worried because many residents have not experienced a tsunami and may ignore warnings because the last two events -- in 1994 and 1996 -- were not destructive, Reed said.

"Be Tsunami Smart" is the theme of this April's Tsunami Awareness Month, held annually in Hawaii to commemorate the 1946 April Fools' Day tsunami and inform people about tsunamis.

"One of the messages we try to get out is that we will be struck by another destructive tsunami at some point," Charles McCreery, director of the Pacific Tsunami Warning Center at Ewa Beach, stressed. That goes especially for surfers and sightseers who flock to the beaches despite sirens. "Tsunami waves are not surfable," emphasizes Brian Yanagi, Hawaii State Civil Defense Earthquake and Tsunami Program manager. They appear and recede, and after the ocean floor is exposed, water rushes in like a flash flood over beaches and roads, he said. A tsunami is a series of extremely long waves triggered by underwater earthquakes or landslides that vertically displace the water. The waves roar across the ocean at 500 mph and may continue arriving for several hours after reaching shore. Surges of water carry debris inland, destroying everything in their path. Most tsunamis are generated by distant earthquakes, and the first warning generally is three hours before the first wave, he said.

IF A LARGE EARTHQUAKE OCCURS on the Big Island, he said, "The waves will wrap around the island within minutes ... so if you feel the ground shaking and you can't stand and you're along the coastline, you need to head to higher ground and inland immediately.

"This is your only warning for a locally generated tsunami."

A tsunami watch may be issued for a distant tsunami resulting from an earthquake greater than 7.5 magnitude in the Pacific "Rim of Fire," Yanagi said. "The public needs to prepare to evacuate coastlines in a tsunami watch -- generally three to six hours before a wave arrives."

If it is confirmed that a tsunami is headed for the Hawaiian Islands, the watch will be upgraded to a warning within three hours of arrival time.

On Oahu, if people cannot get out of densely populated Waikiki, they can go vertically -- above the third floor in steel or reinforced concrete buildings of six or more stories, Yanagi said.

Despite many large earthquakes in the Pacific "Rim of Fire" since 1960, there has been a "quiet" period with no destructive distant tsunamis to Hawaii, he said.

The last damaging tsunami in Hawaii was generated from Kalapana, on the Big Island, by a 7.2-magnitude earthquake, he said. Most of the destruction occurred on that island, and two campers were killed.

In 1960 an earthquake in Chile launched a tsunami that killed 61 people in Hawaii.

THE APRIL 1, 1946, TSUNAMI was the worst natural disaster recorded in island history. After hitting Hawaii, it struck the Marquesas Islands in French Polynesia and continued to Antarctica.

Scientists still are trying to figure it out.

It was believed generated by a magnitude-7 earthquake in the Aleutian Islands, but the waves were too big for the size of the earthquake, said Gerard Fryer, University of Hawaii geophysicist.

He has been studying the tsunami's effects in the Marquesas with other scientists and says, "We have absolutely convinced ourselves the source of that was a landslide rather than an earthquake, which has interesting complications for the tsunami warning system."



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