A few minutes later, a second quake occurred with a preliminary magnitude of 6.3.
The quake was felt as far south as the capital, Santiago, and in Antofagasta, 826 miles further north.
The Chilean Navy said there was no possibility of a tsunami, but some damage was reported in the area.
The National Emergency Office of the interior ministry told Reuters there had been some localized power cuts and rubble covering roads around the region.
A swimming pool on the roof of an apartment block in the city of Copiapo in the Atacama desert had also reportedly overflowed.
Video from the scene showed windows rattling and items falling to the ground.
Local radio stations reported that boulders broke off hills with minor landslides reported.
Electricity was also briefly cut off in the area, but there were no immediate reports of casualties or major damage.
Dozens of aftershocks were also reported around the Huasco region, midway between regional capital La Serena and Copiapo.
Chile is located along the volatile Ring of Fire seismic fault system that circles the Pacific Ocean and often experiences large earthquakes.
This area is the location of most of Earth's subduction zones, where oceanic plates slide under the lighter continental plates.
Earthquakes tend to happen when those plates scrape or subside underneath each other, and when that happens at sea it can spawn tsunamis.
The last major quake in Chile, on Feb. 27, 2010, set off tsunamis and killed 526 people.
The Associated Press contributed to this report.