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Study suggests Nile flood sank ancient cities
NEW YORK (AP) - A new study says that Nile flooding - not earthquakes - sank two ancient cities recently discovered just off Egypt's Mediterranean coast.
The cities of Canopus and Herakleion were found in about eight metres of water in Abu Qir Bay, east of Alexandria, in a discovery announced last year. They had thrived during Greek and Byzantine times, and were later the setting of conflicts between Christianity and pagan religions.
Then during the eighth century A.D. they suddenly disappeared.
In Thursday's issue of the journal Nature, geologist Jean-Daniel Stanley of the Smithsonian Institution and two colleagues from the European Institute of Nautical Archaeology in Paris argue that flooding did the cities in.
When the cities were first discovered, archeologists had assumed that an earthquake sent them to their watery end. Stanford University geologist Amos Nur, who has also studied the site, still prefers that theory.
''We have identified three earthquakes that probably devastated the city in the eighth century,'' Nur said.
But Stanley insists that flooding is a better explanation, even though it is an earthquake-prone area.
Herakleion and Canopus were built on extremely marshy ground at the mouth of the Nile Delta. When a particularly severe Nile flood happened in 741 or 742 - about the time that the cities are thought to have slipped beneath the waves - they were primed for destruction, Stanley said.
He theorizes that the floodwaters compressed the soft ground beneath the cities, causing underground mud flows and even squirting some up through cracks. Buildings would have toppled. If the cities' foundations became unstable enough, they could have slid wholesale into the sea.
''Phenomena like this are known. It's just that usually there aren't cities built on the edges of deltas,'' Stanley said.
Even so, Nur favours shaking as the destructive force. Earthquakes are known to liquefy saturated soil. So if a quake shook the mud beneath Canopus and Herakleion, they easily could have slid into the sea, he said.