The United States Geological Survey said the quake hit at 23:03 GMT, and was centered about 54 kilometers (33 miles) southwest of the town of Coquimbo. It had a depth of about 10 kilometers (6.2 miles), it said.
The Pacific Tsunami Watch Center in Hawaii did not immediately issue a watch or warning, and there were no immediate reports of damage.
Quake-prone Chile remains on watch for major seismic activity since a huge February 2010 earthquake struck the region, killing more than 200 people. It left a trail of twisted buildings and sent tsunami waves roaring across the Pacific Ocean.
Highways in the South American nation of 16 million were sliced to ribbons, bridges toppled and buildings reduced to rubble after that 8.8-magnitude earthquake struck some 325 kilometers (200 miles) southwest of the capital Santiago.