A 6.0-magnitude quake struck northeastern Japan on Tuesday, the US Geological Survey said, but Japanese authorities noted that no tsunami warning was issued.
The quake hit at 8:00 pm (1100 GMT), off Iwate prefecture in the Pacific with the focus estimated some 10 kilometres (6.2 miles) below sea level, the USGS said.
The Japanese meteorological agency had earlier rated its magnitude at 6.4, saying: "Sea levels may change slightly because of the earthquake, but there is no fear of damage from it."
There were no reports of damage at nuclear facilities in the area affected by Tuesday's quake, Japanese public broadcaster NHK said.
Local media also said there were no immediate reports of casualties or injuries following the jolt.
A 9.0-magnitude earthquake triggered a monster tsunami on March 11 last year in northeastern Japan, which killed more than 19,000 people and crippled Japan's Fukushima nuclear plant, sparking an ongoing crisis.