While the deadly tsunami in the Indian Ocean has focused attention on that part of the world, great waves also pose a threat to the United States.
A tsunami struck the Virgin Islands in 1867 claiming 23 lives, and geologic evidence shows giant waves have struck several times over the last 3,500 years, affecting what is now Washington, Oregon and northern California.
“We’re not trying to scare you, we’re just trying to inform you,” Kevin Krajicik said Tuesday, opening a Smithsonian Institution-sponsored panel discussion of U.S. vulnerability to tsunami. Krajicik wrote an article on tsunami scheduled for the March issue of Smithsonian magazine.
“It’s a matter of when, not if,” another tsunami will strike, added George A. Maul, head of the department of marine and environmental systems at the Florida Institute of Technology.
A 1755 earthquake that devastated Lisbon, Portugal, generated a wave that caused damage in the Caribbean, he noted.
And there have been reports of a potential threat to the East Coast of the United States from waves that could be generated by landslides in the Canary Islands, across the Atlantic, added James F. Luhr, a volcanologist at the Smithsonian’s National Museum of Natural History.
While one-fourth of the world’s tsunami occur in the Pacific Ocean, Maul noted that they can occur on any coast.
For example, on the American side of the Atlantic Ocean, more than 2,500 people have been killed in the last 150 years by these waves striking the Virgin Islands, Panama, Jamaica, Puerto Rico, the Dominican Republic and even Canada, Maul added. The most recent, in 1991, killed two people in Costa Rica.
A U.S. tsunami warning program has been in operation about 10 years, focusing largely on Hawaii, Alaska and the Pacific Northwest, where damaging waves have been recorded in recent history, noted Laura S.L. Kong, director of the International Tsunami Warning Center in Hawaii.
Tsunami, caused by undersea earthquakes or volcanoes, can travel across the ocean at the speed of a jet plane, suddenly rising up to as high as 90 feet when they reach the shore, she said.
Joanne Bourgeois, a University of Washington geologist, said sedimentary evidence indicates six or seven severe tsunami have struck that state’s coast over the last 3,500 years, averaging about one such wave every 500 years.
Timothy J. Walsh, chief geologist at the Washington Department of Natural Resources, said public education is essential with millions of people moving into danger-prone coastal areas.
“Citizens must know where to evacuate from and where to evacuate to,” Walsh said.
In Washington, he said, poles are being erected in hazard areas with sirens attached to NOAA Weather Radios. Operated by the National Oceanic and Atmospheric Administration, they can turn themselves on when activated by a broadcast tone. The radios could then both activate the sirens and broadcast the warning over loudspeakers in the affected area.
Hazard maps are being developed to direct people to safer areas in an emergency, he said. Research is also under way on new building standards, with engineers studying what survived the Indian Ocean tsunami to make recommendations for standards in danger areas.
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