Posted on 12/26/2004 8:07:22 PM PST by Strategerist
The earthquake that struck northwest of Sumatra, Indonesia, at dawn yesterday was a perfect wave-making machine, and the lack of a tsunami warning system in the Indian Ocean essentially guaranteed the devastation that swept coastal communities around southern Asia, experts said.
Although waves swamped parts of the Sumatran coast and nearby islands within minutes, there would have been time to alert more distant communities if the Indian Ocean had a warning network like that in the Pacific, said Dr. Tad Murty, an expert on the region's tsunamis who is affiliated with the University of Manitoba in Winnipeg.
Within 15 minutes of the earthquake, in fact, scientists running the existing tsunami warning system for the Pacific, where such waves are far more common, sent an alert from their Honolulu hub to 26 participating countries, including Thailand and Indonesia, that destructive waves might be generated by the Sumatra tremors.
But there was no way to convey that information speedily to countries or communities an ocean away, said Dr. Laura S. L. Kong, a Commerce Department seismologist and director of the International Tsunami Information Center, an office run under the auspices of the United Nations.
Phone calls were hurriedly made to countries in the Indian Ocean danger zone, she said, but not with the speed that comes from pre-established emergency planning.
"Outside the Pacific these things don't occur very often at all so the challenge is how to make people and government officials aware," she said.
Tsunamis, sometimes referred to as tidal waves but having nothing to do with tidal forces, are generated when an earthquake, eruption or landslide abruptly moves the seabed, jolting the waters above.
Resulting waves can cross thousands of miles of deep ocean at near jetliner speeds as near-invisible disturbances before welling up in shallower coastal waters to heights of 30 feet or more.
But even at such speeds, prompt warnings can provide ample time to evacuate people, Dr. Murty and other experts said. The Pacific network of stations gauging wave and earthquake activity is able to alert potential targets within minutes.
Tsunamis have swept the Indian Ocean, as well, oceanographers said yesterday, noting one that killed several hundred people near Bombay in 1945 and another - one of the earliest tsunamis recorded in the region - that ravaged what is now Bangladesh and other parts of the Bay of Bengal in 1762.
With population densities enormously high in many parts of coastal southern Asia, the region should have started setting up such a network long ago, said Dr. Murty, who is originally from India.
Other scientists have voiced similar concerns. At a meeting in June of the Intergovernmental Oceanographic Commission, a United Nations body, experts concluded that the "Indian Ocean has a significant threat from both local and distant tsunamis" and should have a warning network.
But Dr. Murty said that India, Thailand, Malaysia and other countries in the region had "never shown the initiative to do anything."
"They see this as a Pacific problem," he said. "I have a feeling that after this tragedy that may change."
The earthquake near Sumatra was the fifth most potent in the world in the last 100 years and the worst in 40 years, registering a magnitude of 9.0. It was followed by more than a dozen aftershocks, but none of those was expected to produce dangerous waves, said federal geologists.
The quake occurred at one of the many seams in the ever-shifting crust of the Earth where one plate slips beneath another in an incessant, but spasmodic process. In this case, the quake was set off by an abrupt slippage along 700 miles of the seam where the plate beneath the Indian ocean slides under the Indonesian archipelago.
This caused a vast stretch of seabed to shift about 50 feet, said geologists at the National Earthquake Information Center in Golden, Colo.
The biggest danger from earthquakes on land tends to come when the earth heaves horizontally, as is the case along the San Andreas fault in California. But faults where earthquakes tend to cause abrupt vertical motion, like the ones along western Indonesia, pose the biggest risk of generating tsunamis because they can act like a giant piston, deforming the sea. In such submarine earthquakes, gravity and the incompressibility of water force the seas above to react immediately to the change thousands of feet below.
"You're taking hundreds of miles of ocean bottom and moving it dozens of feet," said David Wald, a seismologist at the center. "That displaces a huge amount of water. The water at the surface starts to shift downhill and that makes a tsunami."
Most research on such waves and efforts to create warning systems have focused on the Pacific, where the Ring of Fire, a great arcing seam of volcanic and tectonic activity, causes a significant tsunami about once a decade.
One of the first efforts to alert communities to impending tsunamis came in Hawaii in the 1920's, said Dr. George D. Curtis, a tsunami expert affiliated with the University of Hawaii at Hilo.
A geologist at Hawaii's volcano observatory, upon detecting telltale tremors, would call local harbor officials and tell them to have boats moved to safety, Dr. Curtis said. Efforts greatly intensified in 1946, after a powerful earthquake in the Aleutian island chain of Alaska unexpectedly sent waves smashing into Hawaii, killing more than 150 people.
In 1948, the United States created its Pacific Tsunami Warning Center, which has been linked to an international data and warning network since 1965.
Any underwater earthquake with a magnitude greater than 6.5 starts the process, Dr. Murty said, and if a single wave gauge signals that the ocean is reacting, an alert is issued. The system has helped prevent loss of life, but only in places where alerts can quickly be communicated.
The last catastrophic tsunami occurred in July 1998, when more than 2,500 villagers on the coast of Papua New Guinea died after a magnitude 7.0 earthquake caused an undersea landslide.
But there has been little work done outside the Pacific, other than informal discussions, to expand the tsunami monitoring network.
"There's no reason for a single individual to get killed in a tsunami," Dr. Murty said. "The waves are totally predictable. We have travel-time charts covering all of the Indian Ocean. From where this earthquake happened to hit, the travel time for waves to hit the tip of India was four hours. That's enough time for a warning."
Other experts agreed that the Indian Ocean region could reduce its vulnerability with a warning system, but said no one should expect a quick fix.
Realize there tends to be a lot of contempt for scientists on FR....but they weren't the ones that dropped the ball here; it's, as is usual in big natural disasters like this, or Nevado del Ruiz, the big problem comes from governmental officials.
Question: How long before this gets to be George Bushs fault?
Global warming will be increased due to the change in patterns of flow of the currents after the earthquake.
Not for real scientists.............just those who've sold their souls to the liberal devil (global warming would be a good example of scientists whose graves I'd gladly spit on).
Real scientists have built the very building blocks of our modern society
I haven't seen it. Only contempt for the pseudo scientists with their global warming B.S.
Question: How long before this gets to be George Bush's fault?
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Sheesh... it's already his fault. That's why he's on vacation... so he can relax and therefore make believe he knew nothing whatsoever about the coming tragedy. But we know the truth about his clever deception schemes, don't we??? ;-))
Why blame anyone, these are very poor countries, the only people with the means to flee are those with motorcycles and wealthy tourists, you obviously dont understand profound poverty.
Scientists from Algore's paradise.
Don't you worry, I'm sure they are hard at work at it. Tune into see-BS news tomorrow night for all the details.
Who do you think measures these earthquakes? Go do some research.
There are too many people around walking vetically that cannot try to figure out the effects of 'cause and effect.'
O h well, leave it up to the school teachers to teach our children to count to ten. There's only so many digits on two hands. DUH!
This country is so intellectually dumbed-down; it is beyond pathetic.
Silly FReepers...The tsumani/earthquake isn't a result of global warming, it is a result of BUSH/CHENEY/HALLIBURTON OIL DRILLING!
I dunno, I'm just asking.
Did the tsunami hit the base at USAF Diego Garcia? Any damage reports?
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