A publication of the Archaeological Institute of America
The Inka mountaintop site of Machu Picchu is not about to collapse, as reported by Japanese scientist Kyoji Sassa of Kyoto University, whose alarmist prediction appeared in the March 7 issue of New Scientist and was picked up by the international press. Sassa cited evidence of foundation cracks in the Principal Temple, debris flows down the backside of the Intihuatana, or "hitching post for the sun," which was damaged in August 2000 during the filming of a beer commercial (see "Inka Beer Bash," November/December 2000, p. 21), and recent ground settling near the Temple of the Sun.
According to Colorado civil engineer Kenneth Wright, the foundation failure in the Principal Temple occurred while it was under construction; the Inka abandoned the project leaving the building incomplete. Little has changed, he says, since Yale University explorer Hiram Bingham photographed the structure in 1912. As for the debris flows, "It is a common occurrence on steep slopes where rainfall approaches 80 inches per year. Such debris flows tend to be superficial and not necessarily signs of deep-seated geological problems. Settlement near the Temple of the Sun is judged to be of modern origin, due to poor water handling at Fountain No. 3 by the modern-day Machu Picchu management."
"Sassa was correct about Machu Picchu being landslide prone," says Wright, but "he did not fully understand the Inka genius for slope stabilization. In the Machu Picchu area steep, high cliffs are common and the natural soils are in constant battle against gravity, but the Inka engineers knew this and handled the situation by building hundreds of well-designed terraces for erosion control, as well as agricultural production." Wright estimates that 60 percent of the construction at Machu Picchu is belowground site preparation and building and wall foundations.