Recent investigations based on the integration of Earth observation technologies with a few trial trenches revealed the image of Machu Picchu before that the monumental architecture began to be built. These investigations unveiled that from a drainage basin it was transformed into a quarry, then into a plaza, until it became the masterpiece of Inca architecture that the whole world knows. This is what was discovered, combining remote sensing and geophysical surveys by as part of the international Itaca mission of Cnr in Peru
Machu Picchu, iconic monument of the Inca civilization, one of the seven wonders of the modern world, is always a source of attraction not only because of its disarming beauty and fragility, but also because of the continuous discoveries that archaeological research is able to return.
Recent investigations based on the integration of Earth observation technologies with a few trial trenches revealed the image of Machu Picchu before that the monumental architecture began to be built. These investigations unveiled that from a drainage basin it was transformed into a quarry, then into a plaza, until it became the masterpiece of Inca architecture that the whole world knows. This is what was discovered, combining remote sensing and geophysical surveys by as part of the international Itaca mission of Cnr in Peru. The study is published in Scientific Reports (Nature), and was carried out by the National Research Council of Italy (Cnr) through the Institute of Heritage Sciences (Cnr-Ispc) and the Institute of Methodologies for Environmental Analysis (Cnr-Imaa) in Potenza, in collaboration with other Italian and polish research teams.
"The construction history of a site is partially preserved underground and is usually revealed through classical archaeological investigations," says Nicola Masini, a Cnr-Ispc researcher and coordinator of the Itaca mission. "In the case of Machu Picchu, since it is no longer possible to carry out extensive archaeological excavations, it becomes important to integrate information acquired in the past with non invasive imaging technologies, including remote sensing and geophysics".
The study revealed the preparatory stages of construction of the monumental site, when Machu Picchu was a construction site where workers and laborers were engaged in quarrying and transporting stones, carrying out drainage works and stabilizing steep slopes
"The integration of satellite and drone imaging, with different geophysical techniques (georadar, geomagnetic and geoelectric), and a few trial trenches (already carried out in the subsurface of the Plaza Principal by Jose Bastante former Director of Machu Picchu Park) revealed a construction history as surprising as it is unknown," continues Rosa Lasaponara, CNR-Imaa researcher.
“Underneath the present square, our investigations revealed the presence of a reservoir that later was turned into a quarry and subsequently drainage works were carried out with the prospect of filling it in to create the plaza " Masini points out. "The square in its turn has been built in two phases: the first was a plaza hundida, or sunken plaza used for ritual activities; the second is the current Plaza Principal, located between the two architectural sectors of the Hurin and Hanan, visited by thousands of tourists every day."
The approach used has brought new insides to the history preserved in the subsurface of Machu Picchu, related to the preparatory construction phases that rarely comes to light except through extensive and destructive excavation campaigns or, alternatively, as demonstrated by the Italian researchers, by maximizing in areal terms the information content of small assays and surveys, combining and integrating different methods and technologies of non-invasive investigation based on geophysics and remote sensing.
Cnr Press Office
- Masini, N., Romano, G., Sieczkowska, D., Capozzoli L., Spizzichino D., Gabellone F., Bastante J., Scavone M., Sileo M., Abate N., Margottini C., Lasaponara R. Non invasive subsurface imaging to investigate the site evolution of Machu Picchu. Scientific Re