Machu Picchu intentionally built on faults

The Incan sanctuary of Machu Picchu — considered one of humanity’s greatest architectural achievements — was intentionally built in a location where tectonic faults meet, according to a study. Built in a remote Andean setting atop a narrow ridge high above a precipitous river canyon in Peru, The UNESCO World Heritage Site is renowned for its perfect integration with the spectacular landscape.

However, the 15th-century sanctuary’s location has long puzzled scientists who wonder why the Incas built their masterpiece in such an inaccessible place. According to Rualdo Menegat, a geologist at Brazil’s Federal University of Rio Grande do Sul, the Incas intentionally built Machu Picchu — as well as some of their cities — in locations where tectonic faults meet.

“Machu Pichu’s location is not a coincidence. It would be impossible to build such a site in the high mountains if the substrate was not fractured,” said Menegat. Menegat found that these faults and fractures occur in several sets, some of which correspond to the major fault zones responsible for uplifting the Central Andes Mountains during the past eight million years. Because some of these faults are oriented northeast-southwest and others trend northwest-southeast, they collectively create an “X” shape where they intersect beneath Machu Picchu. Construction of the sanctuary in such a high perch also had the benefit of isolating the site from avalanches and landslides, alltoo-common hazards in this alpine environment, Menegat said.

The faults and fractures underlying Machu Picchu also helped drain the site during the intense rainstorms prevalent in the region.