Evacuations have also been ordered in southern Peru, CNN's Shasta Darlington reports.
The Pacific Tsunami Warning Center is still evaluating whether a tsunami threat exists for Hawaii.
The highest waves measured so far have been 6.9 feet in Iquique, just 59 miles northwest of the earthquake's epicenter.
Chile's Centro Sismologico Nacional reports at least four significant aftershocks of magnitude 5.0 and higher in the immediate aftermath of the quake.
Residents are being evacuated in coastal cities as far south as Valparaiso, just west of the capital Santiago, La Tercera newspaper reports.
The quake caused a small landslide but no deaths or major damage to houses, according to Chilean Deputy Interior Minister Mahmud Aleuy.
Deputy Interior Minister Aleuy says there are reports of traffic jams as people try to evacuate. Pictures from CNN Chile show residents walking quickly, but calmly through the streets.
According to the Global Disaster Alert and Coordination System – a joint effort that includes the United Nations – the northern Chilean city of Iquique has a population of more than 200,000 people.
The latest bulletin from the Pacific Tsunami Warning Center now has Chile, Peru, Ecuador, Colombia and Panama under a tsunami warning. Costa Rica, Nicaragua, El Salvador, Guatemala, Mexico and Honduras are under a tsunami watch.
The area where the quake struck has seen significant seismic activity in recent weeks. On March 16, a 6.7-magnitude earthquake struck 37 miles west-northwest of Iquique, according to USGS. A 6.1-magnitude struck the same area exactly one week earlier.
There is damage reported at an air traffic control tower at the airport in Iquique, according to El Mercurio, a national newspaper.
Gerard Fryer, a geophysicist with the Pacific Tsunami Warning Center, tells CNN that there is “clearly not going to be any hazards to the coastline of North America." The center is still in a wait-and-see mode on Hawaii and New Zealand.
Kurt Hertrampf, who owns operates a hostel about 1.5 kilometers from the Pacific Ocean in Chile, tells CNN: "It was a strong, strong earthquake. I'm still a little bit worried because of the tsunami warning." Still, he told CNN that he doesn't plan to evacuate."
CNN Chile reports that the Iquique airport is closed.
At least 100,000 people are evacuating the coast of the Valparaiso region, Radio Bio Bio's website says, citing the superintendent of the region, Ricardo Bravo.
More than 60 fore shocks magnitude 4 or larger preceded the earthquake since March 15, says Rich Briggs of the U.S. Geological Survey.
President Michele Bachelet suspended her scheduled activities for Wednesday and will evaluate visiting the area affected by the earthquake, La Tercera reported.
Mark Simons, a professor at the California Institute of Technology, tells CNN the last time this area had an earthquake about this magnitude was 1877. Nearby plates have been moving toward Chile and Peru at around 8 centimeters a year. So a large earthquake has been expected. "This earthquake as big as the one we would expect to be here, so we are somewhat concerned is still a much larger earthquake waiting to happen."
All tsunami watches and warnings previously issued have been canceled except for tsunami warnings for Chile and Peru, the Pacific Tsunami Center announced.
Chile's Ministry of National Emergency and Public Safety says the first tsunami waves have reached Pisagua, Iquique and Patache.
About 300 inmates escaped from a jail in Iquique, authorities said. The Investigative Police of Chile said 16 had already been recaptured. Chile’s Interior Minister Rodrigo Peñailillo says 100 more security forces are being flown to the city.
The Pacific Tsunami Warning Center is "still evaluating" whether to issue a tsunami warning for Hawaii in the wake of a large earthquake off Chile's coast, said Charles McCreery, the center's director. He estimated that a decision will be made within about an hour. He said an advisory could be issued indicating threats for swimmers due to strong currents, "but no real flooding of the land."