We show that the Inca developers intentionally chose cross-tectonic faults to build their cities. Indeed, in Machu Picchu, the rocks were so fragmented that it was possible to build cities in high topographic levels, strategically safe against both geological hazards and inhospitable Andean conditions.
Did the Incas have any understanding of tectonic faults?
So did the Incas have any understanding of tectonic faults, or did they simply choose the site for Machu Picchu based on the fact that it was rich in fractured rock? Menegat thinks that while the Incas may not have known what the fractures were, they could have recognized them.
Why was Machu Picchu built where faults intersect?
“The principal result was the discovery that Machu Picchu was built where geological faults intersect,” Menegat explained. Rualdo Menegat Rualdo Menegat explained that the already fractured blocks of rock usually came in shapes that naturally fit together.
What did Menegat discover about the geography of Machu Picchu?
Menegat found that Machu Picchu’s main buildings and stairs were all oriented along the directions of these faults. He also noticed that other Inca settlements like Cusco, Pisac, and Ollantaytambo were built atop fault line intersections as well.
How was Machu Picchu formed?
In the Andes, a series of earthquakes on two faults, named the Machu Pichu fault and the Huayna Picchu fault, uplifted the steep peaks with the same names and formed the ridgetop where Machu Picchu is located. During those earthquakes, a large section of rock was down-dropped between the two faults in a geologic structure known as a graben.
Which Inca settlements were built on top of fault intersections?
The research also showed that some other Inca settlements in the region—such as Ollantaytambo, Pisac and Cusco—were also built on top of fault intersections, like Machu Picchu.
What were the advantages of the area at the intersection of faults?
Furthermore, the area at the intersection of faults may have provided other advantages. For example, the faults could have acted as a source of water, channeling rain and ice melt directly into the site. This allowed the Incas to build away from the bottom of valleys, where any settlement would have been at risk from flooding and avalanches.
What did Menegat find about Machu Picchu?
Furthermore, Menegat found that Machu Picchu's main sectors, buildings and stairs all appear to be oriented along the directions of these faults. "The principal result was the discovery that Machu Picchu was built where geological faults intersect," Menegat said.
What is the X shape of Machu Picchu?
Menegat's investigations showed that the UNESCO World Heritage Site sits right above the mutual intersection of three main fault directions, and two secondary directions that run north-south and east-west, which almost form an "X' shape. Furthermore, Menegat found that Machu Picchu's main sectors, buildings and stairs all appear to be oriented along the directions of these faults.
How long is the fault line in Machu Picchu?
For his research, Menegat used satellite imagery and field measurements to map the network of faults—some of which measure up to around 110 miles long—in the area beneath Machu Picchu.
When was Machu Picchu built?
The general consensus is that the Incas built Machu Picchu around 1450, however, the site was later abandoned during the Spanish conquest.
Which civilization ruled over vast swathes of South America's Andean region in the 15?
The Incas —a civilization that ruled over vast swathes of South America's Andean region in the 15th and 16th centuries—intentionally built Machu Picchu, and other cites, in a location where tectonic faults meet, research suggests.
Where did the Incas take advantage of pre-existing fractures in local stones?
Ollantaytambo, Peru: The Incas took advantage of pre-existing fractures in local stones to reduce the amount of energy needed to create their master stonework. Photo taken 21 July 2016,
What were the faults and fractures that underlying Machu Picchu?
The faults and fractures underlying Machu Picchu also helped drain the site during the intense rainstorms prevalent in the region . “About two-thirds of the effort to build the sanctuary involved constructing subsurface drainages,” says Menegat. “The preexisting fractures aided this process and help account for its remarkable preservation,” he says. “Machu Picchu clearly shows us that the Incan civilization was an empire of fractured rocks.”
What were the advantages of the Incas?
Chief among these was a ready source of water. “The area’s tectonic faults channeled meltwater and rainwater straight to the site,” he says. Construction of the sanctuary in such a high perch also had the benefit of isolating the site from avalanches and landslides, all-too-common hazards in this alpine environment, Menegat explains.
What is the significance of Machu Picchu?
The ancient Incan sanctuary of Machu Picchu is considered one of humanity’s greatest architectural achievements. Built in a remote Andean setting atop a narrow ridge high above a precipitous river canyon, the site is renowned for its perfect integration with the spectacular landscape.
What were the natural features of the Incas?
The Incas had a deep respect for the dynamic world that surrounded them, and they recognized many natural features as sacred and powerful, including rock outcrops, mountains, rivers, caves, and springs. By deliberately integrating important buildings, gardens, and shrines into the natural setting of the landscape, the Incas expressed relationships to their gods and their kinship groups.
How did the Andes Mountains rise?
Fast-forward two hundred million years and the Andes Mountains began to rise as tectonic plates collided along the western edge of South America. Extreme compressive forces build mountain ranges by essentially squeezing the rock and forcing it upwards into mountains. Push the edge of a rug and watch wrinkles develop and grow taller - a similar process happens when mountains are built.
What are the two major systems that intersect in an X shape beneath Machu Picchu?
These occur in two major systems that intersect in an "X" shape beneath Machu Picchu. The set that includes the Machu Picchu and Huayna Picchu faults is oriented northeast-southwest; the second set is oriented northwest-southeast. These joint sets, together with the Machu Picchu fault, were critical factors in the site selection and successful construction of Machu Picchu.
What is the name of the mountain behind Machu Picchu?
Machu Picchu citadel, with the mountain Huanya Picchu behind the site. (Photo: Roseanne Chambers)
What is the impact of high rainfall on Machu Picchu?
High seasonal rainfall (nearly 2,000 mm; 79 in) is slowly breaking down the minerals in the granitic rocks, providing material susceptible to landslides. By locating Machu Picchu on a ridge, the Inca builders protected the city from these dangers. The ridgetop setting also provided excellent natural defenses.
What is the most famous archaeological site in the world?
Machu Picchu, iconic symbol of the Inca Empire, is one of the most widely recognized and admired archaeological sites on Earth. The Incas ingeniously integrated their buildings into the natural environment, taking advantage of the unique geology of this part of the Andes Mountains in southern Peru. Built over 500 years ago, it is in a spectacular location on a narrow ridge between two mountain peaks.
How do earthquakes happen?
Rocks can deform up to a point, but after that limit is reached, the built-up stress is violently and instantaneously released in an earthquake. As the stored energy that has been locked in the rocks is released, an earthquake will propagate along a fault , somewhat like unzipping a zipper or collapsing a line of dominoes. In the Andes, a series of earthquakes on two faults, named the Machu Pichu fault and the Huayna Picchu fault, uplifted the steep peaks with the same names and formed the ridgetop where Machu Picchu is located. During those earthquakes, a large section of rock was down-dropped between the two faults in a geologic structure known as a graben. Machu Picchu is built in this graben.
Which Inca settlements were built on fault lines?
He also noticed that other Inca settlements like Cusco, Pisac, and Ollantaytambo were built atop fault line intersections as well.
What would the Incas have built on?
By building on these fracture zones between blocks of rock in the Earth’s crust, the Incas would have had a built-in abundance of building materials in the form of pre-fractured stone. The faults might have also served as an efficient water source, with rain and melted ice washing directly into the site, without the risks of flooding of a city built in a valley
What was the reason for choosing this extreme location?
Rualdo Menegat The reasoning for choosing this extreme location was three-fold (protection against earthquakes, a water supply, and readily available building materials), but all resulted from one factor: fault lines.
How many people lived in Machu Picchu?
Machu Picchu is comprised of more than 200 individual structures, and was populated by 1,000 people at the height of the Inca Empire. A UNESCO World Heritage Site since 1983, the city’s construction has confounded people since its modern discovery in 1911. “It could not be built on a whim.
How long did the Incan citadel last?
The Incan citadel of Machu Picchu is one of the most stunning yet confounding pieces of architecture known to man, lasting for 600 years high atop the Peruvian Andes.
Which direction does the underground confluence run?
The underground confluence — marked by three main fault directions and two secondary fault directions that run north-south and east-west — nearly form an X shape. Menegat found that Machu Picchu’s main buildings and stairs were all oriented along the directions of these faults.
Did the Incas use mortar?
Menegat said it would be “impossible” to build at such heights without rocks already fractured, and that the Incas didn’t even need to use mortar for these perfectly compatible stones to fit together. According to National Geographic, these stones “dance” and fall into their intended places when earthquakes occur.