(CN) — Nine thousand years ago, a Mediterranean tsunami as much as 150 feet high swept across the spot where the ancient settlement of Tel Dor in northwest Israel would later be built.
A study published today in the journal PLOS ONE describes a large early Holocene tsunami deposit between 9,910 to 9,290 years ago in coastal sediments at Tel Dor, a maritime city-mound occupied from the Middle Bronze II period through the times of the Crusades.
The ancient wave appears to have traveled as much as two miles inland, depositing marine shell and sand across freshwater wetlands. Though tsunamis aren't uncommon along the eastern Mediterranean coastline, happening once a decade or so, most travel only about 1,000 feet inland, less than a quarter of a mile.
Local tsunamis tend to arise due to earthquakes in the Dead Sea Fault system and submarine landslides. The study authors note an earthquake from around the same time period has already been identified using cave damage in the nearby Carmel ridge, suggesting that this specific earthquake could have triggered an underwater landslide that caused the tsunami at Tel Dor.
By taking into account the pattern of Bronze-period settlements in the surrounding area, the study authors suggest the tsunami could have wiped out one or several Neolithic settlements and created a 4,000-year gap in the archaeological record for the area.
To conduct their analysis, study authors Gilad Shtienberg, Richard Norris and Thomas Levy from the Scripps Center for Marine Archaeology at the University of California, San Diego, and colleagues from Utah State University and the University of Haifa used photogrammetric remote sensing techniques to create a digital model of the Tel Dor site, combined with underwater excavation and terrestrial borehole drilling to a depth of 29.5 feet.
“Our project focuses on reconstructing ancient climate and environmental change over the past 12,000 years along the Israeli coast; and we never dreamed of finding evidence of a prehistoric tsunami in Israel,” said Shtienberg, a post-doctoral student at the Scripps Center for Marine Archaeology who is studying the sediment cores. “Scholars know that at the beginning of the Neolithic, around 10,000 years ago, the seashore was 4 kilometers (2.5 miles) from where it is today. When we cut the cores open in San Diego and started seeing a marine shell layer embedded in the dry Neolithic landscape, we knew we hit the jackpot.”
By comparison, the deadly and devastating 2011 tsunami that swept across parts of Japan reached about 130 feet, though its precise height may never be known since the earthquake that caused the tsunami and the tsunami itself destroyed tide gauges and triggered communication failures along the coast.
The largest tsunami in recorded history hit at Lituya Bay in southeastern Alaska on July 9, 1958. The wave, recorded at an astonishing 1,720 feet, did not cause much damage because it struck in an isolated and geologically unique setting.
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