Which 1960 earthquake in Chile is the strongest ever recorded by instruments?

The 1960 Valdivia earthquake was the strongest earthquake ever recorded by instruments.

It struck southern Chile on 22 May 1960 and is commonly assigned a moment magnitude of 9.5. The rupture affected roughly 1,000 kilometres of the Chilean coastline, where the Nazca Plate is being forced beneath the South American Plate.

The earthquake generated a Pacific-wide tsunami. Waves reached Chile, Hawaii, Japan, the Philippines, New Zealand, and other locations, showing how ocean-basin earthquakes can produce hazards far from the rupture itself.

The event is often called the Great Chilean earthquake. It is distinct from the 1964 Alaska earthquake and the 2004 Indian Ocean earthquake, both of which were also megathrust earthquakes but had lower recorded magnitudes.