Chile's navy cancelled a tsunami alert for all of the coastline on Thursday following a strong 7.6 magnitude quake off the north of the country a day earlier.

It was the strongest of several aftershocks that followed a huge 8.2-magnitude quake blamed for six deaths in the same region on Tuesday.

The aftershock was centred 19 kilometres south of Iquique at a depth of 40 kilometres, the U.S. Geological Survey said. It was originally reported to be 7.8 magnitude, but was later downgraded to 7.6 magnitude.

Chile's emergency office, Onemi, which had earlier asked residents to evacuate the coastline, said "people can return to their homes."

With files from The Associated Press