About 800 miles west of Beijing, along a 30-mile stretch of the Yellow River, researchers found a variety of sediments, indicating a landslide, a lake and a violent flood in the distant past. Based on the extent of these deposits, they were able to reconstruct the catastrophic events: A landslide dammed the river, forming a lake several hundred feet deep. After several months the dam burst, releasing a torrent of nearly 100 million gallons of water per second.
Flood sediment settled over collapsed buildings and crushed bodies some 15 miles downstream at the archaeological site of Lajia. But the waters didn’t flatten the village or kill its residents — an earthquake caused the death and destruction, and probably also triggered the dam collapse that led to the flood.
By radiocarbon dating human bones and rubble at Lajia, researchers placed the flood at approximately 1920 B.C., roughly coincident with Yu’s legendary dynasty.