Archaeologists have unearthed evidence of the largest earthquake ever experienced by humans. The 9.5-magnitude earthquake caused a tsunami of less than 8,000 kilometers and prevented humans from setting foot near the coast for about a thousand years.
1960 was always believed to be the largest earthquake recorded in Valdivia south of Chile. It ranged from 9.4 to 9.6 on the Richter scale. 6,000 people died and tsunamis swept across the Pacific. But research published in Science Advances shows even bigger earthquakes in the past.
About 3,900 years ago an earthquake struck what we know as northern Chile. A tectonic platform then raised the shore. It was followed by a tsunami that was so powerful that it created waves about twenty meters high. Those waves traveled as far as New Zealand, where rocks the size of cars spun inland.
Didn’t go to the beach for 1,000 years
Both earthquakes are described as ‘megathrusts’ or ‘mega earthquakes’, which are the most powerful earthquakes in the world. They occur when one of the Earth’s tectonic plates is pushed under another. Both plates are trapped in this way, but the seismic forces continue to increase. The tension is such that a large crack forms at the junction of the plates. This creates a giant decay, resulting in the release of energy with catastrophic seismic waves.
“We have found evidence of marine sediments and many animals living quietly in the ocean,” said James Koff, a geologist and research associate professor at the University of Southampton in the UK. “We saw it all very high and inland, so it could not be a storm.”
According to archaeologists, the ancient stone structures that can be excavated are also evidence of a mega-earthquake. “The locals had nothing. And our excavations show that it was a social catastrophe that took place later. The tsunamis displaced people inland and made it more than 1,000 years for people to live on the beach. It’s amazing that people at that time relied so heavily on the sea for food,” he said.