The 1960 Valdivia earthquake, also called the Great Chilean earthquake, struck southern Chile on 22 May 1960 with a moment magnitude of 9.5 — the most powerful earthquake ever recorded by instruments.
The rupture ran roughly 800 km along the boundary where the Nazca Plate dives beneath the South American Plate. It triggered a Pacific-wide tsunami that killed people as far away as Hawaii, Japan and the Philippines, and it set off the eruption of the Cordón Caulle volcano days later.
Estimates of the death toll range widely, from about 1,655 to several thousand, with around two million people left homeless. Because so much of the energy was released offshore, the tsunami — not the shaking alone — caused a large share of the destruction. Valdivia remains the benchmark against which every other great earthquake is measured.
NOAA's historical tsunami database shows just how far that energy travelled: the wave reached Hilo, Hawaii in under 15 hours with a run-up near 10 metres, killing 61 people, then struck Japan around a day later — some 17,000 km from the epicentre — killing more than 100 more. It is one of the clearest demonstrations that a mega-thrust earthquake's danger is not confined to its own coastline.