A strong magnitude 6.9 earthquake struck northern Japan on Thursday, the country's weather agency said, and was felt hundreds of kilometres away in Tokyo, though authorities reported no casualties and issued no tsunami warning.
No major damage was immediately reported, but some Shinkansen bullet train services were suspended after the quake struck off Iwate prefecture on Japan's main island of Honshu.
The quake struck at a depth of 50 kilometres, the Japan Meteorological Agency (JMA) said.
One woman in the town of Hashikami in neighbouring Aomori prefecture, where the shaking was strongest, told AFP that the only damage in her home was a photo frame falling down.
Footage on public broadcaster NHK showed regular traffic in Hachinohe city with traffic lights still functioning as normal.
"At this time, there is no information indicating any human casualties, but we will continue to monitor and assess the situation regarding damage," top government spokesman Minoru Kihara said.
So far, there were no abnormal changes at radiation monitoring posts linked to the Tomari nuclear plant on the main northern island of Hokkaido, NHK reported.
In Aomori, the tremors registered an upper six on Japan's seven-level Shindo intensity scale.
At that level, people may be unable to remain standing without support and can be thrown off their feet, while unsecured furniture is likely to topple and windows may shatter, according to the JMA.
Prime Minister Sanae Takaichi ordered ministries and government agencies to work closely with local authorities.
"I ask residents in areas that experienced strong shaking to remain alert for the possibility of additional earthquakes of similar intensity," Takaichi said on X.
Japan is one of the world's most seismically active countries, sitting on top of four major tectonic plates along the western edge of the Pacific "Ring of Fire".
The archipelago, home to around 125 million people, typically experiences hundreds of jolts every year and accounts for about 18 percent of the world's earthquakes.
The vast majority are mild, although the damage they cause varies according to their location and the depth below the Earth's surface at which they strike.
It is haunted by the memory of a massive 9.0-magnitude undersea quake in 2011, which triggered a tsunami that killed or left missing around 18,500 people and wrecked the Fukushima nuclear plant.
On April 20 this year, a tremor measuring 7.7 hit the country's north in Pacific waters off Iwate prefecture, injuring at least 10 people and shaking large buildings in Tokyo.
This prompted authorities to issue a special advisory on Monday warning of an increased risk of earthquakes of magnitude 8.0 or stronger.
The advisory was lifted after a week.
