TOKYO (Reuters) - There were no immediate reports of damage after northern Japan was hit by an earthquake which the Japan Meteorological Agency said had a preliminary magnitude of 6.8.
A tsunami warning was issued but later lifted, with waves measured off the coast significantly lower than an initial estimated height of 50 cm (20 inches).
There were no reports of abnormalities at the Higashidori and Onagawa nuclear power plants in northern Japan, domestic media reported. Reactors at both plants had been shut down for routine maintenance when the quake hit.
On March 11, 2011, the country's northeast coast was struck by a magnitude 9 quake, the strongest in Japan on record, and a big tsunami, which triggered the world's worst nuclear crisis in 25 years since Chernobyl. The disaster killed about 20,000 people.
(Reporting by Tokyo news room; Editing by Joseph Radford)