Assessing the tsunami threat to the East Coast

06:01 PM EDT on Friday, May 3, 2002

By Craig Moeller, 13Weather Meterologist

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Hampton Roads and North Carolina are used to dealing with bad weather, nor'easters, hurricanes, flooding. But there could be another threat lurking off our coast. Even though there hasn't been a tsunami caused death along the East coast in the last 300 years, researchers are still assessing the true risk of one and watching for signs.

Residents of the Pacific coast have always dealt with the horrors of massive tidal waves and tsunamis.

Since 1992, tsunamis have claimed more than 2,000 lives worldwide. Tsunami is Japanese for "harbor wave." Actually, it's a series of waves set in motion by something that suddenly displaces a large amount of water.

Three things set them off.

1) A massive object crashing into the ocean. That's the least likely event to occur. Scientists say that may happen once every 10 to 20 thousand years.

2) The sudden collapse or explosion of a volcanic island could trigger a tsunami. Geologists are watching La Palma in the Canary Islands. In theory, a volcano there could set off a huge landslide creating a "mega-tsunami." Researchers say the waves could be 30 to 180 feet high by the time they'd reach Hampton Roads. But again, the odds of such an event are extremely low and we'd likely have weeks of early warning and activity leading up to a collapse.

3) The most common way tsunamis begin is by underwater earthquakes and landslides. Those events produce waves 10 to 30 feet above normal. This one's drawing more attention along the East Coast.

Thanks to improved sensing technology, NOAA's National Ocean Service is able to draw the ocean floor in exact detail. The mapping found cracks in the ocean floor, about 100 miles from our coastline. These cracks could spark underwater landslides and trigger tsunamis.

Norfolk Emergency Services is not looking past the tsunami threat. "We had a regional meeting through the Hampton Roads Emergency Management Committee. We discussed it with our navy peers and just talked about what we would do. Really it was to make sure that if there were a threat we would have the warning time as early as possible," said Jim Talbot, director of NES.

Everyone agrees that best way to deal with tsunami is to have as much advance warning as possible. James Dixon with the National Oceanic and Atmospheric Administration has been monitoring tide levels in the Chesapeake Bay for the past 17 years. "The Atlantic coast seaboard is a quiet seaboard as far as earthquakes. Therefore the probabilities are very, very low of having a large tsunami activity in this ocean. However the international community would still like to see an enhancement to the tsunami program on the atlantic ocean seaboards."

If a slide just offshore ever happens, the Atlantic coast would have 30 minutes to an hour to react. "In an emergency, using two-way radios and all-terrain vehicles, lifeguards can clear the entire oceanfront and Sandbridge in about four minutes."

But until an early detection system is in place, experts advise us to get away from the water when you see a fast receding tide or a fast advancing tide because the people how take fast action are the ones who usually survive.