Two people died of heart attacks during the quake, but there were no reports of other fatalities or significant damage.
Rockslides blocked stretches of some highways outside Santiago and the facades of some older buildings in Valparaiso fell to the ground.
The shaking also knocked out power and telephone service around Santiago as it awakened residents across a wide area of the capital district just before midnight on April 16.
Parts of central Chile were devastated in February 2010 by an 8.8 magnitude temblor that killed hundreds of people.