Scientists Find Cracks Off N.C. Coast Which Could Cause Tsunamis
Posted May 1, 2000
RALEIGH — Hurricane season is nothing new to North Carolinians, but what about tsunamis? Scientists says they have found cracks in the ocean floor about 100 miles off the Virginia-North Carolina coast, which could lead to their formation.
Tsunamis are formed when the continental shelf is not stable and the sea floor slides down like an underwater avalanche triggering giant waves. They are mainly found in the Pacific Ocean.
A tsunami killed 2,000 people along the coast of Papua, New Guinea two years ago. Walls of water raced ashore wiping out entire villages.
Oceanographers say if an undersea avalanche or earthquake happened along the 25-mile section of the continental shelf where the cracks were located, a huge wave could sweep across the Virginia-North Carolina coastline.
N.C. State researcher Dr. Robert Knowles says such a wave would move fast.
"You have a wall of water which moves very, very rapidly," Knowles says. "It could be coming in 35, 40 to 45 miles an hour."
Researchers use animation which shows the forces of the waves moving away from the center of the displacement of huge amounts of sea water. Unlike a hurricane, a tsunami cannot be predicted, and that is the danger.
"If it were to occur on the shelf, it would be fairly close. So if there were an earthquake, there would be probably no warning time," Knowles says.
Scientists from Woods Hole, Columbia and the University of Texas say wave heights could be up to 20 feet high -- similar to the storm surge of aCategory 4hurricane.
"If there were a major displacement then there could be a major tsunami created with certainly Category 4 or even higher waves that would come in that we would have to worry about on our coast," Knowles says. "It could be very catastrophic."
Scientists say if a crack does exist and it is extremely old, the threat of activity is less.
Scientists plan an expedition this weekend off the coast to gather more information. They say there is evidence that a huge tsunami occurred in the area 16,000 to 18,000 years ago.