Four men and one woman died - two who suffered heart attacks and three who were crushed, said Interior Minister Rodrigo Penailillo.
About 300 prisoners escaped from the northern port city of Iquique in the immediate aftermath, he said.
The quake struck about 8:46 p.m. local time, some 60 miles northwest of Iquique. It had a depth of 12.5 miles, the U.S. Geological Survey said.
Chile's National Emergency Office asked coastal residents to evacuate.
"The fact is, we will know the extent of the damage as time goes by and when we inspect the areas in the light of day," Chile's President Michelle Bachelet said early Wednesday. "The country has faced these first emergency hours very well."
Residents in the port city of Antofagasta walked calmly through the streets to higher ground as traffic piled up in places.
"Many people are fearful after experiencing the powerful earthquake in 2010, so they immediately fled for higher ground when they heard the tsunami warning," said Fabrizio Guzman, World Vision emergency communications manager in Chile.
"There have been multiple aftershocks and communications have been cut off in many of the affected areas. So people are waiting in the dark hills not knowing what is to come, and hoping they will be able to return to their homes safely."
The Pacific Tsunami Warning Center issued several tsunami warnings, but canceled all of them by early Wednesday. Tsunami watches, which initially extended as far north as Mexico's Pacific coast, were called off as well.
Tsunami waves of more than 6 feet generated by the earthquake washed ashore on the coast of Pisagua, according to Victor Sardino, with the center.
Iquique, with a population of more than 200,000, saw 7-foot waves.
An earthquake of the scale that struck Tuesday night is capable of wreaking tremendous havoc.
So, if the initial reports stand, Chile may have dodged a major catastrophe.
Landslides damaged roads in some regions. Power and phone outages were reported in others.
Chile is on the so-called "Ring of Fire," an arc of volcanoes and fault lines circling the Pacific Basic that is prone to frequent earthquakes and volcanic eruptions.
On March 16, a 6.7-magnitude earthquake struck 37 miles west-northwest of Iquique. A 6.1-magnitude hit the same area a week later.
About 500 people were killed when an 8.8-magnitude earthquake struck Chile on February 27, 2010. That quake triggered a tsunami that toppled buildings, particularly in the Maule region along the coast.
According to researchers, the earthquake was violent enough to move the Chilean city of Concepcion at least 10 feet westward and Santiago about 11 inches to the west-southwest.
'No hazards' to U.S. coastline
The U.S. National Tsunami Warning Center worked Tuesday to determine the level of danger for Alaska, Washington, Oregon and California, as well as Canada's British Columbia.
Gerard Fryer, a geophysicist with the Pacific Tsunami Warning Center, told CNN there is "clearly not going to be any hazards to the coastline of North America."
The Pacific Tsunami Warning Center issued a tsunami warning for Hawaii, saying strong currents may pose a hazard to swimmers and boaters.