Tsunamis are known to destabilize soft marine sediments, the team notes, leaving telltale coverings of clay deposits after they reach land.
These deposits identify Mount Etna as the source of the tsunami and discount other possible causes, such as an asteroid strike or an undersea earthquake, the team says.
The researchers also speculate that a Neolithic village just off the coast of present-day Israel was hit by the tsunami.
The well-preserved Atlit-Yam settlement, which due to altered sea levels today lies submerged, “shows evidence of a sudden abandonment” 7,000 to 8,000 years ago, the researchers write.
These signs include a pile of gutted fish that had been processed and then “stored for future consumption,” which was discovered buried under a layer of clay.
Further research by the Pisa-based team will investigate whether secondary tsunamis were set off by the sediment flows triggered by the initial tsunami from the Mount Etna collapse.
Pareschi said the probability of a new big collapse on Etna is low, but she added, “the eastern sector of the volcano is sliding toward the sea, and we have to understand very well the triggering mechanisms.”
If the Etna tsunami had happened today, she said, the impact would be catastrophic, because the eastern Mediterranean coast is so densely populated.
(Read “Etna Volcano Becoming Dangerous, Experts Warn” [February 6, 2003].)
Some ten percent of tsunamis worldwide occur in the Mediterranean.
The most recent volcano-triggered tsunami was caused by a landslide on the Italian island of Stromboli in the Tyrrhenian Sea in 2002.
The volume of the landslide “was however a thousand times smaller than the Mount Etna one,” Pareschi said.
A tsunami early warning system is currently being developed for the Mediterranean and the northeastern Atlantic. Due to become operational in December 2007, it will form part of a global tsunami warning system coordinated by the United Nations Educational, Scientific and Cultural Organization (UNESCO).
The measure follows in the wake of the devastating Indian Ocean tsunami, caused by an earthquake in December 2004, which struck coastlines with little or no warning.
Pareschi says the ancient Etna tsunami would have been comparable with the 2004 event, which claimed around 275,000 live.
I got caught in a very minor tsunami in the Med about ten years ago. When in the water, a big wave just surged right up the beach and unceremoniously dumped us all onto the sand. A bit scary, but not more than a half a metre high. The only thing to distinguish it from a big wave was the drawback and the fact it surged right up the beach. All this reading about tsunamis makes me edgy about living half a male from the sea on a dead flat piece of coast.
The theory being knocked around at present is that the melting ice at the end of the ice age caused mega tsunamis because the shifting weight triggered earthquakes, that started the tsunamis. This would really have put a dent in any civillisation that was trying retreating from rising sea levels. The regular tsunamis might explain why there’s a big stone ships achor half way up a big hill in the near east too.