Three years after the devastating tsunami that destroyed coastal communities around the Indian Ocean, the exact death toll remains uncertain. But survivors' tales of similarly massive waves sweeping in from the ocean are passed down by elders in certain communities and may be enough to save lives in the event of another disaster like the 2004 Indian Ocean tsunami, a researcher says.
The tsunami that struck the coasts of Thailand, India and Indonesia on December 26, 2004 caused very high mortality in the affected regions, with anywhere from 10 to 90 percent of local populations being killed depending on the location.
The region-wide death toll is estimated to have exceeded 200,000.
But a similarly intense tsunami that struck northern Papua New Guinea in 1930 caused a fraction of the deaths compared to the 2004 disaster, with only 0.1 percent to 1 percent of the coastal population being killed.
The key to this lower death toll were stories of tsunamis that had been passed down across the generations to the area residents, said tsunami researcher Simon Day, a visiting professor at the University of California, Santa Cruz, who has been researching evidence of ancient tsunamis in Papua New Guinea.
"Oral traditions are a very efficient means of tsunami education," Day said. Day presented his findings at a recent meeting of the American Geophysical Union.
While Day and his colleagues were searching for evidence of past giant tsunami, they visited local villages and asked local leaders for permission to explore the land, and the local people told them of stories of past tsunamis (that Day and his colleagues linked to physical evidence showing that the tsunamis likely actually took place) that had been passed down across generations of people who lived on the island hundreds of years ago.
"It became apparent that oral traditions were going back 500 years," Day said. "The stories contained information about how to recognize a tsunami was about to come, such as falling sea levels, and told how people should take action. That’s the reason why casualties [in 1930] were so low."
In contrast, many people in Thailand in 2004 did not recognize the warning signs of the tsunami and did not know to seek refuge inland. Day said this difference is likely due to higher immigrant population in the area with no indigenous knowledge of tsunamis, like that that the people of Papua New Guinea possess. He based this statement on his reviews of past research and writings.
Day said that these oral traditions were effective even if locals didn’t base them on science.
"In Papua New Guinea, there’s no such thing as a natural disaster — it’s always blamed on sorcery by a rival tribe," Day said.
Day says that a coordinated effort to spread these stories to vulnerable populations could reduce deaths in the event of another catastrophic tsunami, such as the Indian Ocean disaster.