The quake struck at 11:45 a.m. local time and was centered about 90 miles (150 kilometers) off the northeastern coast—about 270 miles (440 kilometers) northeast of Tokyo—at a depth of about 6.2 miles (10 kilometers), Japan's meteorological agency said.
A 24-inch (60-centimeter) tsunami reached the coastal town of Ofunato, in Iwate prefecture, with other towns reporting smaller waves reaching shore about 30 minutes after the quake.
"We have confirmed that small tsunami have come up on the shores, but we have no reports of damage at this point," said Shinobu Nagano, an emergency and disaster response official in Iwate. "We are still trying to determine the impact of the quake."
Some train lines in the area were temporarily stopped after the quake, but they were restarted shortly after noon. Tohoku Electric Power said there was no damage at its nuclear power facility in the region.
The Pacific Tsunami Warning Center in Hawaii said a Pacific-wide tsunami was not expected.
There was a 6.3 magnitude aftershock shortly after the main quake, the meteorological agency said.