Researchers speak with people from Aitape in Papua New Guinea, near where a skull - now thought to have belonged to the world's oldest known tsunami victim - was found in 1929. Photo / Ethan Cochrane
Researchers speak with people from Aitape in Papua New Guinea, near where a skull - now thought to have belonged to the world's oldest known tsunami victim - was found in 1929. Photo / Ethan Cochrane
Kiwi researchers have helped reveal what is thought to be the world's oldest known tsunami victim.
A new geological analysis of a site where a 6000-year-old human skull was discovered in Papua New Guinea in 1929 has shown how the person probably died in a catastrophic tsunami.
Researchers behind the study, published today in the journal PLOS ONE, found that the place where the skull was unearthed was a coastal lagoon that was inundated by a large tsunami about 6000 years ago.
It was likely a similar event to the tsunami that struck nearby with such devastating effect in 1998, killing more than 2000 people.
"We conclude that this person who died there so long ago is probably the oldest known tsunami victim in the world," said the study's first author, Honorary Professor James Goff, of the University of New South Wales.
The partially preserved skull was discovered almost 90 years ago by Australian geologist Paul Hossfeld at a site which is about 12km inland from the northern coast of Papua New Guinea, near the modern town of Aitape.
Dr Ethan Cochrane, a senior lecturer in anthropology at the University of Auckland, jointly designed the research and led the field team with colleagues from New Zealand, Papua New Guinea, Australia and the US.
"We tramped several kilometres up Paniri Creek leading into the Torricelli mountains to find the area where the skull was originally retrieved," Cochrane said.
"[Hossfeld] simply took the skull from exposed geological deposits, so our goal was to acquire sediment and biological samples from the deposits to learn more about the natural environments in which the individual died thousands of years ago."
The team carried out laboratory tests on the sediment to look at grain size and its geochemistry.
They found the microscopic silica shells of diatoms, small single-cell organisms that live in water and are sensitive indicators of water characteristics such as temperature, salinity, and the amount of water movement.
"We used the diatoms to learn more about the water in the area around the time of the individual's death," Cochrane said.
The Aitape Skull was found in 1929 near the town of Aitape in Papua New Guinea. Photo / Arthur Durband
"The sediments that the Aitape skull was in have pure marine diatoms in them, which indicates ocean water was inundating the area, which currently is 12km inland.
"It's also really high-energy ocean water - high-energy enough for these little tiny specks of silica that the diatoms build to be broken as they're washing in from the sea."
The high-energy water combined with chemical signatures and specific sediment grain sizes all indicate the presence of a tsunami at the time the skull was buried, Cochrane said.
"It's possible that the skull was buried before and it was washed out as the tsunami came across, but based on observations of modern tsunamis, we don't think that's likely."
Cochrane hoped this study would help raise awareness about how people adapt and thrive in coastal areas that are subject to tropical storms, earthquakes and tsunamis.
People likely started moving from the mountains to the coastlines in the area around 6000 years ago, he said.
"The interesting question is why do people move into this tectonically active, environmentally dangerous area beginning 6000 years ago, and why do they stay there?"
He suggested it could be because New Guinea's north coast was also very productive in food resources.
"So perhaps people are balancing risk and food reward.
"Understanding these kind of adaptive trade-offs will be key to mitigating risk and ensuring the livelihoods of coastal populations today."
