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Unformatted text preview: fact sheet • tsunami detection and warnings U.S. DEPARTMENT OF COMMERCE • U.S. DEPARTMENT OF THE INTERIOR T sunamis are a series of very long waves generated by any rapid, large-scale disturbance of the sea. Most are generated by sea floor displacements from large undersea earthquakes, the remainder produced by volcanoes and large undersea landslides. A tsunami can exceed 500 mph in the deep ocean but slows to 20 or 30 mph in the shallow water near land. Tsunamis can cause great destruction and loss of life within minutes on shores near their source, and some tsunamis can cause destruction within hours across an entire ocean basin. Approximately 85 percent of tsunamis occur in the Pacific region but they are known to happen in every ocean and sea. Before December 26, 2004, the last cross-ocean tsunami in the Indian Ocean that resulted in thousands of casualties and widespread destruction occurred in 1883. Although infrequent, tsunamis are a significant natural hazard with great destructive potential. They can only be dealt with effectively through programs of warning, mitigation, and education. The National Oceanic and Atmospheric Administration (NOAA) oversees the U.S. Tsunami Program with its mission to provide a 24-hour detection and warning system and increase public awareness about the threat of tsunamis. NOAA operates two tsunami warning centers that continuously monitor data from seismological and tidal stations, evaluate earthquakes that have the potential to generate tsunamis and disseminate tsunami information and warning bulletins to government authorities. The U.S. Geological Survey contributes to tsunami warning by providing high-quality data from global and national seismic station networks, by issuing accurate and timely earthquake alerts and assessments, and through basic research on historical tsunamis and their effects. The Pacific Tsunami Warning Center in Hawaii and the West Coast/Alaska Tsunami Warning Center in Alaska are the operational centers of the 24-hour U.S. tsunami warning system for the Pacific Rim. The Pacific Tsunami Warning Center provides warnings for tsunamis to most countries in the Pacific basin. The U.N. Intergovernmental Oceanographic Commission established the International Coordination Group for the Tsunami Warning System in the Pacific in 1968. Its function is to assure that tsunami watches, warnings, and advisory bulletins are disseminated throughout the Pacific to 26 member states....
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This note was uploaded on 07/31/2011 for the course GLY 4921 taught by Professor Snow,e during the Spring '08 term at University of South Florida - Tampa.
- Spring '08