Onagawa and Higashidori nuclear plants, located near the epicenter showed no signs of disorders, Kyodo news agency reported citing operating company Tohoku Electric Power Co.
Earlier on Tuesday, another quake of magnitude 6.7 hit northern Japanese coast some 83 kilometers (52 miles) to the northeast of the town of Miyako. Japan Meteorological Agency issued a warning tsunami advisory shortly after the quake due to possibility of strong currents, but lifted it later.
Japan is situated in a seismically active zone, with earthquakes of magnitude 6 and higher often taking place in the island nation.
In March 2011, the country saw a devastating 9 magnitude quake, which triggered a series of massive tsunami waves that led to a partial meltdown of several reactors at the Fukushima Daiichi nuclear power plant. The catastrophe left almost 16,000 people dead.
