A second powerful earthquake has struck off northern Chile, a day after the region was hit by a deadly 8.2 magnitude tremor.

The 7.6 magnitude quake rattled buildings and triggered a new round of evacuations, although a tsunami alert issued for coastal communities was soon lifted.

It also caused a number of landslides near Alto Hospicio, a poor area in the hills above the port town of Iquique, where 2,500 homes and many fishing boats were damaged by Tuesday's quake.

Chilean President Michelle Bachelet, who had travelled to nearby Arica to see how the city had been affected by the earlier disaster, was among those who fled a hotel.

"I was evacuated like all citizens" she tweeted soon afterwards. "One can see that the people are prepared".

Authorities said six people were killed in Tuesday's earthquake but said further victims may be found as rescuers search older buildings in remote areas. Schools in northern Chile remain closed amid fears of more aftershocks.

People living in the area have been expecting major tremors for years. However, the so-called mega-quake many residents fear may be yet happen, according to Paul Earle, a seismologist at the US Geological Survey (USGS).

Chile is especially vulnerable to earthquakes because the Nazca and South American tectonic plates rub up against each other off the country's west coast.

Officials had reinforced emergency procedures after an unusually large amount of seismic activity in recent weeks, while residents had prepared by stocking up on food and rehearsing evacuation plans.

Tuesday's quake was located 14 miles south of Iquique at a depth of about 25 miles, according to the USGS.