Thursday, May 19

Mega-earthquake and tsunami devastated Atacama 3,800 years ago | Digital Trends Spanish

A 9.5-magnitude earthquake and subsequent tsunami with waves up to 20 meters (66 feet) devastated South America 3,800 years ago. Research on the Pacific coast was documented by scientists from the University of Chile and published in the journal Science Advances.

The movement occurred in northern Chile, near the border with Peru, due to the contact of the Nazca and South American plates. The waves entered through the coast of the Atacama desert, the driest in the world and home to the most modern astronomical observatories on the planet.

“The high magnitude reached by this earthquake and tsunami caused such an impact that it could have strongly decimated coastal populations,” reported the institution. After the cataclysm, scientists warned of “important changes in the ways of human life.”

Archaeologist Diego Salazar explained that the “event could generate a very high mortality among people.” The hypothesis established that perhaps it also motivated “the migration of a significant number of people to other territories.”

Credit: University of Chile.

In turn, the geologist Gabriel Easton reported ancient beaches (“paleobeaches”) located at heights between 4.0 and 7.0 meters (13 and 23 feet) from the sea. Its formation “cannot be explained by global changes in sea level, but by tectonic uplift as a result of large earthquakes,” he argued.

In his geoarchaeological exploration, the academic also recorded signs of the earthquake on the ground of the Atacama desert. “What we see here is a crack that affects the archaeological layers that reach an age of approximately 4,000 years,” he pointed out.

According to the University of Chile, the cataclysm produced drastic changes in the ways of inhabiting and relating to coastal communities over hundreds of kilometers. In Salazar’s words, “after the occurrence of the event, there are still people in the territory, but with less density.”

“In the next 1,000 years, the population seems to recover, because the cemeteries reappear, the sites are larger and more numerous, which suggests that the demographics are beginning to recover. But settlements and cemeteries place them higher and farther from the coast than they were before the event,” he added.

The earthquake and tsunami of 3,800 years ago had a magnitude similar to the largest ever recorded in the Chilean city of Valdivia in 1960. Salazar indicated that “it is likely that, on larger time scales, the earthquakes occurred with magnitudes that we do not have on record and to we may not be so well prepared.”

Finally, the study suggested the possibility of an earthquake of similar magnitude occurring off the coast of northern Chile. “Management plans have to be calibrated based on this possibility, with a view to reducing disaster risk,” the expert concluded.

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