Why the impressive city-state of Teotihuacán – one of the most important pre-Hispanic centers of power in Central America – disappeared is one of the great mysteries of world archaeology. Experts agree that it went from housing more than 100,000 inhabitants in the 2nd century to just under 5,000 in the 7th. Wars, epidemics? Now the study
The ancient culture of Teotihuacán affected by megaearthquakes during the Early Epiclassic Period
, which has just been published in the scientific journal
Journal of Archaeological Science: Reports
,
offers a surprising answer: five major seismic movements, which occurred approximately between the years 100 and 650, They destroyed or seriously damaged its main buildings and directly led to the collapse of this civilization, despite the desperate efforts of its inhabitants to try to rebuild what nature denied them.
“The possibility that the megaearthquakes of the Mesoamerican Trench (Pacific coast) could be responsible for the damage does not conflict with other existing theories about its collapse, considering that the sudden superposition of natural disasters such as earthquakes could increase internal wars, the uprisings and civil unrest,” indicates the article signed by specialists from the Geological and Mining Institute of Spain (IGME-CSIC), the universities of Barcelona, Salamanca, Autonomous of Madrid, Politécnica and Michoacana of San Nicolás Hidalgo (Mexico).
The Teotihuacan culture flourished in the Central Valley of Mexico between the years 150 and 650. It was a civilization that built a society that was capable of building splendid pyramids and beautiful temples. Specialists believe that its spectacular and rapid urban and technological growth had its origin, curiously, in two volcanic eruptions between the 50s and 300s, which devastated the also thriving city of Cuicuilco. Its disappearance under the lava and ashes cleared the way to Teotihuacán.
This city-state extended approximately 22 square kilometers at its peak. It is estimated that about 100,000 people lived there, although some authors raise the figure to 200,000. It had three main buildings: the pyramids of the Sun (65 meters high) and the Moon (45 meters), as well as the temple of the Feathered Serpent or Quetzalcóatl. Around them, the residential areas of the middle and upper classes were grouped. The urban layout was organized along a large avenue of more than two kilometers (Avenida de los Muertos), facing north.
But from the year 550, there was “a sharp decrease in the population, continued fires and collapsed buildings.” These events mark what is known as the Epiclassic Cultural Period of the Central Sierra of Mexico: in the face of so many misfortunes, the Teotihuacans decided to abandon the city and settled in nearby Xochicalco and Tula, which in turn gave rise to the flourishing of a new culture, the Toltec.
To reach its conclusions, the report - signed by experts Raúl Pérez, Natalia Moragas, Javier Elez, Pablo Silva, Jorge Giner, Miguel Ángel Rodríguez-Pascua, Adrià Ramos, María A. Perucha, Elvira Roquero and Víctor Garuño - is based on detailed study of the so-called EAE (archaeological effects of earthquakes, from its acronym in English) observed in the temple of the Feathered Serpent and the pyramids of the Sun and the Moon, in addition to the archaeological information compiled by other experts in previous years.
Spanish and Mexican specialists believe that the megaearthquakes that destroyed the city originated in the so-called Mesoamerican Trench in the Pacific Ocean. “The spatial pattern of the EAEs indicates a direction of the seismic shock with a southwest to northeast direction. This means that the Mesoamerican Trench could be the source. In this case, megaearthquakes coming from it could explain the EAEs and the seismic intensity that affected the city so seriously." However, they admit, the earthquakes could have had another origin, a place close to the city, although they consider it less likely.
What they are clear about is that there were five enormous earthquakes, between the years 100 and 650, that forced the Teotihuacans to modify and reinforce their architectural style in the pyramids of the Sun and the Moon, as well as in the reconstruction of the Temple of the Feathered Serpent. They sought to minimize the effects of new earthquakes. But these works were not enough given the magnitude of the earthquakes that were going to arrive. An example of these anti-seismic measures are the well-known “locking” of the ashlars, which prevent the horizontal movement of the stone blocks, as the Incas did in Machu Picchu, for example.
Specifically, according to experts, the city suffered “at least two strong destructive earthquakes (Intensity VIII-IX), which had a great impact on the development of architectural and construction styles.” The first occurred between the years 1 and 150 and the second between the years 405 and 505.
Three other earthquakes, although of lower intensity (Intensity VIII) also affected the city around the years 225, 400 and 600. “The conjugated action of ancient tectonic movements can explain the archaeoseismic damage documented in some places, but the two The latter, before its abandonment in 650, are the most probable cause.
The EAEs described include broken and fragile corners affecting the western stairs of the Pyramid of the Sun and the new and old temples of the Feathered Serpent. They completely rule out, and based on scientific evidence, that this damage could be due to deliberate human breakage or climatic erosion of the basalt stones of the stairs.
“The combination of the high seismic energy released by repetitive earthquakes, the amplitude of the frequency and the sediment filling of Lake Texcoco (about 50 kilometers away) could explain the deformation patterns observed in the pyramids and temples throughout the entire the history of Teotihuacán”, they point out. Finally, they demand an “exhaustive analysis of the liquefaction and deformation of the soft sediments of the lake,” because it would help establish the exact date when the inhabitants of Teotihuacán surrendered to the force of nature.
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