The temblor struck at midnight Friday (1 a.m. PST Saturday) and was centered about 60 miles west of Craig, Alaska, the U.S. Geological Survey said.
The tsunami followed minutes later and was eventually expanded to include coastal areas from Cape Fairweather, Alaska, to the northern tip of Vancouver Island, Canada — an area extending more than 700 miles.
A center had warned that "significant widespread inundation of land is expected," adding that dangerous coastal flooding was possible.
In its cancellation statement, the center said that some areas were seeing just small sea level changes.
"A tsunami was generated during this event but no longer poses a threat," the center said.
After one community reported seeing just a small wave, the police in the coastal town of Cordova said they had no reports of any problems.
The Alaska Earthquake Information Center said the quake was widely felt but it received no reports of any damage.
In addition to the warning, a tsunami advisory was briefly in effect for some Alaska coastal areas to the north of the warning zone, as well as to the south of the zone, from the Washington state border to the northern tip of Vancouver Island.
A tsunami warning means an area is likely to be hit by a wave, while an advisory means there may be strong currents, but that widespread inundation is not expected to occur.