Lyobaa or Mitla is one of the most emblematic places of pre-Hispanic Mexico. Its name in Zapotec already raises curiosity: ‘Place of Tombs’ or ‘City of the Dead’. It was the eternal resting place of the Zapotec kings and high priests, but at some point in the Postclassic period the inhabitants began to leave the area in a migration movement that had nothing to do with the arrival of the Spanish. This is something that will happen later.

It is estimated that it once housed over 10,000 inhabitants and was one of the most important sites of pre-Hispanic Mexico, along with Mexico City and Teotihuacán. However, Something must have happened to make the population leave. and for years some have held the hypothesis that what occurred was a landslide that buried the city.

This may have happened in the late 15th century, but despite excavations no evidence has been found to support the theory. So far. A team of scientists from the National Institute of Anthropology and History (INAH), the Faculty of Engineering and the Geophysical Institute of the National Autonomous University of Mexico (UNAM) and archaeologists from the ARX Project Association have found in fossils the key to understanding the reason for the abandonment of the ‘House of the Tombs’ in pre-Hispanic times.

Mitla, the Pompeii of Oaxaca

When we talk about the Pompeian disaster, we give all the credit to Vesuvius. This is quite justified because the eruption ended life in the city and burned everyone caught in front of it (which was good for us because it allowed us to preserve the structures in perfect condition, like the papyrus rolls that we decipher and even the genome of a Pompeian).

However, apart from the volcano, Pompeii also suffered an earthquake that caused great damage. It is astonishing to understand that such a magnificent civilization or city could be destroyed at any moment due to a natural disaster.

We know a lot about Pompeii and with the intention of solving the mysteries of Mitla, the Lyobaa Project was born. In addition to INAH and UNAM, the ARX Project also participated in this work. An association that uses non-invasive screening techniques (electrical resistivity tomography, seismic noise reaction tomography and ground-penetrating radars) to investigate the subsurface.

Certainly in Mitla, they have already made great progress by applying these techniques to examine the subsoil of the large Catholic church in the area, discovering a network of tunnels. In the middle of the work, INAH clarifies that the Mitla area is located in a seismically active area. This was also the case with the hypothesis of landslides covering the city, and this claim seems to be confirmed by the applied resonance methods.

Equipment used to investigate underground without excavation

The researchers placed nine surveying stations: three north of the Mitla Archaeological Site, another at the foot of one of the alleged avalanches, two at Adobe and Arroyo, and three more south of the archaeological site. With this non-invasive technique, the team was able to perform an MRI that yielded an interesting result: The subsoil of the entire area consists of irregular layers. It contains components such as ignimbrites and volcanic mud, as well as soft soil deposits.

This would confirm the avalanche hypothesis and lend further validity to previous geological studies that have shown that part of Mitla’s original settlement is buried under a large layer of rock. It has also led researchers to suggest that the collapse that buried the city was caused by a massive earthquake of magnitude six or seven that moved large amounts of dry soil.

This is a good explanation for understanding why the Zapotecs abandoned their great ‘City of the Dead’, and represents another step in the consolidation of these non-invasive exploration techniques that are allowing us to know more and more detail about the subsoil of Mexico and the civilizations that inhabited the region.

“This technology allows us to understand the reasons for Mitla’s abandonment, as well as to make predictions about the state of the structures in the archaeological complex. We must now continue our investigation, because it is clear that Mitla hides much more than meets the eye.”

Images | ARX Project, INAH

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