Mizuno said the operator of the troubled Fukushima plant, Tokyo Electric Power Co., said no damage or abnormalities had been found.
Japan's meteorological agency issued a 1-meter (3-foot) tsunami advisory for a long stretch of Japan's northeastern coast. It put the quake's magnitude at 7.1, while the U.S. Geological Survey recorded a magnitude of 7.3. The U.S. Pacific Tsunami Warning Center did not post warnings for the rest of the Pacific.
The meteorological agency reported tsunamis of 40 centimeters in Kuji city in Iwate prefecture and Soma city in Fukushima, as well as a 20-centimeter tsunami at Ofunato city in Iwate and a 30-centimeter tsunami at Ishinomaki in Miyagi prefecture.
All of Japan's 50 nuclear reactors remain offline as the government decides whether they meet more stringent requirement enacted after the 2011 quake, which triggered multiple meltdowns and massive radiation leaks at the Fukushima plant about 250 kilometers (160 miles) northeast of Tokyo.
A string of mishaps this year at the Fukushima plant has raised international concerns about the operator's ability to tackle the continuing crisis.
Nuclear Regulation Authority Chairman Shinichi Tanaka has scheduled a Monday meeting with Tokyo Electric's president to seek solutions to what he says appear to be fundamental problems.