Tsunami May Have Carried Some Permanently to Sea

Dec. 30, 2004 — -- Some of the people who were swept out to sea by the giant tsunamis that crashed against the shorelines of Asia and East Africa may sadly remain at sea forever, in an ocean grave, scientists say.

The bulk of the force from a tsunami is released as the wave crashes into shore. This means most debris and people may have been carried further inland, say oceanographers. But a giant reverse force is also created as gravity pulls the waves back to the ocean. Like a rip tide on steroids, the rapid return flow of ocean water can suck people and debris out to sea at rapid speeds.

Depending on how far out people or debris are carried, they may be caught up by local coastal currents, which could eventually wash them ashore, or by broader ocean currents that dominate water flow further out at sea.

"These very strong reverse currents don't last long, but they can take things out to sea very fast," said Ricardo Matano, an oceanographer at Oregon State University. "So whatever was taken out to sea may remain there. The question is, how long?"

Lynne Talley, an oceanographer at Scripps Institution of Oceanography at the University of California in San Diego, tracks currents in the affected regions of the Indian Ocean and says one of the main active currents in the Bay of Bengal -- where much of the devastation occurred -- is now the East India coastal current, which flows south and west toward Africa's east coast.

"The currents are complicated in this area because of the monsoons that shift from summer to winter," she said. "The main question is whether debris escapes from the currents along the coastal interior."

While a current such as the East India coastal current could carry some debris for hundreds of miles, human victims may eventually sink, according to Philip Liu, an oceanographer and environmental engineer at Cornell University in Ithaca, N.Y.

The death toll continued to climb as the waters that pulled many out to sea then deposited them on beaches along the coasts of Sri Lanka, India, Sumatra and Indonesia. Rescue workers expected the number of counted dead to rise as more bodies are recovered and disease spreads among survivors.