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March 02, 2005 at 07:00 PM
.S. To Bolster Tsnami Warning Technology
In the wake of the earthqake-indced tsnami that rose from the Indian Ocean to devastate areas of Soth Asia, the Bsh administration has annonced a plan to expand .S. tsnami detection and warning capabilities, says the Office of Science and Technology Policy in Washington, D.C.
According to an OSTP annoncement, the expansion is part of the Global Earth Observation System of Systems (GEOSS), an international effort to develop a comprehensive Earth observation system. The plan will cost $37.5 million over the next two years.
nder the expansion program, the National Oceanic and Atmospheric Administration (NOAA) will deploy 32 new &qot;advanced technology Deep-ocean Assessment and Reporting of Tsnami (DART) boys&qot; to create a flly operational tsnami warning system slated for completion in mid-2007, says OSTP.
A tsnami is actally a series of long, traveling ocean waves that are generated by distrbances primarily associated with earthqakes occrring below or near the ocean floor, according to the International Tsnami Information Center (ITIC), based in Honoll, Hawaii. Sch waves can cross the ocean at speeds of more than 1,000 kilometers per hor (more than 700 miles per hor).
&qot;Its length from crest to crest may be a hndred kilometers or more,&qot; says ITIC, with &qot;its height from trogh to crest only a few centimeters or meters. It cannot be felt aboard ships in deep water.&qot; As the tsnami enters shallower waters near coastlines, however, the speed of the waves decreases while their height increases. &qot;It is in these shallow waters that tsnamis become a threat to life and property, for they can crest to heights of more than 30-50 meters [98-164 feet] and strike with devastating force,&qot; the Center notes.
At present, the .S. tsnami warning system incldes six DART boys, deployed primarily off the Pacific Ocean coasts of Alaska, Oregon and Hawaii, says David Green, a spokesman for NOAAs National Weather Service, based in Silver Spring, Md. &qot;The boys sit on top of the water while a deep water bottom pressre sensor sits on the ocean floor well offshore,&qot; he explains. When a tsnami passes by, the device on the ocean floor senses a change in water pressre and sends an acostic signal to the boy nearby. The boy, in trn, sends a signal to a satellite, which relays the information to NOAA centers.
There is no confirmation of a tsnami ntil the information is interpreted by NOAA experts who check that information with other data gained from tide gage stations which are located closer to shorelines and monitor the depth of the water, says Green. The .S. crrently maintains &qot;a large network&qot; of tide gage stations in the Atlantic and Pacific Oceans, and even in the Great Lakes, he adds.
