January 21, 2009

Demise of early Peruvians discovered

U.S. scientists say a series of earthquakes followed by torrential rains caused the demise of coastal Peruvians more than 3,600 years ago.

This maritime-farming community had been successful for over 2,000 years "¦ and then all of a sudden, 'boom,' said University of Florida Professor Mike Moseley. They just got the props knocked out from under them.

Moseley is one of five authors of a paper to appear in the online edition of the Proceedings of the National Academy of Sciences.

The people of the Supe Valley along the central Peruvian coast flourished for about 2,000 years in the arid desert plain adjacent to productive bays and estuaries by fishing, irrigating fruit orchards and growing cotton and vegetables.

But approximately 3,600 years ago, an enormous earthquake or series of earthquakes struck, destabilizing the mountain ranges surrounding the valley, sending massive amounts of debris crashing into the foothills, the scientists said. Subsequent El Ninos brought torrential rains, washing the debris into the ocean.

Strong ever-present onshore winds resulted in massive sand sheets blowing inland, creating a blasting effect that would have made daily life nearly impossible, Moseley said.

What had for centuries been a productive, if arid, region became all but uninhabitable, the scientists said, with the Supe society eventually collapsing, replaced only gradually by societies relying on the much more modern arts of pottery and weaving.