Scientists discover ancient earthquake, as powerful as the biggest ever recorded
Pabellón de Pica. Uplifted coastal deposits with tsunami deposit comprising shells and large pebbles
A new study has discovered that an ancient super-earthquake took place in Northern Chile, on the same scale as the largest recorded quake in history. The earthquake, 3800 years ago, had a magnitude of around 9.5 and the resulting tsunami struck countries as far away as New Zealand where boulders the size of cars were carried almost a kilometre inland by the waves.
Earthquakes happen when two tectonic plates rub together and rupture - the longer the rupture, the bigger the earthquake. Previously, the largest known event in the world happened in 1960 in Southern Chile.
“It had been thought that there could not be an event of that size in the north of the country simply because you could not get a long enough rupture,” explained Professor James Goff, Visiting Professor at the University of Southampton who co-authored the study. “But we have now found evidence of a rupture that’s about one thousand kilometres long just off the Atacama Desert coast and that is massive,” he continued.
The study was led by Professor Diego Salazar at the University of Chile and has been published in Science Advances.
The research team found that the enormous rupture of the plates caused the coastline of northern Chile to lift up and a massive tsunami was also generated. “The Atacama Desert is one of the driest, most hostile environments in the world and finding evidence of tsunamis there has always been difficult,” explained Prof Goff. “However, we found evidence of marine sediments and a lot of beasties that would have been living quietly in the sea before being thrown inland. And we found all these very high up and a long way inland so it could not have been a storm that put them there.”