The earthquake, which was felt in Tokyo, had a magnitude of 7.4, the Japan Meteorological Service said, and was centered off the coast of Fukushima prefecture at a depth of about 10 km (6 miles).
There were no reports of deaths or serious injuries several hours after the quake hit at 5:59 a.m. (2059 GMT November 21).
A tsunami of up to 1.4 meters (4.5 feet) had been observed around Sendai, about 70 km (45 miles) north of Fukushima, with smaller waves hitting ports elsewhere along the coast, public broadcaster NHK said.
Television footage showed ships moving out to sea from harbors as tsunami warning signals wailed, after warnings of waves of up to 3 meters (10 feet) were issued.
"We saw high waves but nothing that went over the tidal barriers," a man in the city of Iwaki told NTV television network.
The Pacific Tsunami Warning Center in Hawaii said the tsunami threat had now largely passed.
"Sea level fluctuations may continue along some coasts of Japan over the next few hours," it said.
The US Geological Survey measured November 22's quake at magnitude 6.9, down from an initial 7.3.
