The earthquake occurred beneath the Pacific Ocean off the coast of Chile and had a magnitude of 9.5 as assigned by the United States Geological Survey.
The event was a megathrust earthquake that occurred at a depth of about 20 miles where the Nazca Plate is subducting beneath the South American Plate.
A series of foreshocks the previous day had warned of the incipient disaster; one, of magnitude 7.9. The fault-displacement source of the earthquake extended over an estimated 560–620 mile stretch of the Nazca Plate, which subducted under the South American Plate.
The earthquake and their aftereffects killed 5,000 people and leave another 2 million homeless. It caused huge landslides of debris down the mountains of the region, as well as a series of tsunamis. The tsunami raced across the Pacific Ocean with waves as high as 35 ft.
The tsunami traveled hundreds of miles west toward Hawaii, the Philippines and Japan, where hundreds also died. In fact, the waves set off by this earthquake bounced back and forth across the Pacific Ocean for a week.
The coasts of California, New Zealand, Australia and Kamchatka were also affected.
Two days later the Cordón-Caulle volcano in Los Lagos in the Chilean lake district, erupted after nearly 40 years of inactivity, an event thought by some seismologists to be linked to the quake.
Historically, magnitude 8 earthquakes in Chile occur every 10 to 25 years. It is only a matter of time until Chile once again has a super earthquake whose impact, like the 1960 Chile event, will be felt around the world.