The area was shaken by repeated, smaller aftershocks, the agency said.
After the quake, authorities issued a warning that a tsunami potentially as high as 2m could hit. Sirens whooped along the coast as people ran for higher ground.
Ishinomaki, a city in Miyagi, reported a tsunami 1-meter-high and other towns reported smaller tsunamis.
About two hours after the quake struck, the tsunami warning was cancelled. The Pacific Tsunami Warning Center earlier said there was no risk of a widespread tsunami.
Aiko Hibiya, a volunteer for the recovery in Minami-Sanriku, a coastal town devastated by last year's tsunami, said she was at a friend's temporary housing when the quake struck.
