Japan earthquake: Tsunami warning issued after 6.8-magnitude tremor near Niigata

Meteorological agency warns waves of up to 1-metre could strike Honshu's northwestern coast

A tsunami warning has been issued after a magnitude 6.8 earthquake struck close to the coast of Japan.

There were no reports of serious casualties, but the country’s Meteorological Agency issued a warning for a 0.2 to 1-metre tsunami along the northwest coast of the main island of Honshu.

The quake struck around 30 miles southwest of the city of Sakata at 10.22pm, the agency reported, with the coastal areas of Yamagata and Niigata prefectures and the Noto area in Ishikawa Prefecture receiving tsunami advisories.

The agency said the quake’s epicentre was fairly shallow at about six miles below the sea’s surface.

Shallow quakes tend to cause more damage on the Earth’s surface, but the agency said the expected “fluctuation” of waves was unlikely to cause damage.

A map provided by the USGS showing the location of the earthquake (USGS)

Footage showed surveillance cameras on buildings in Niigata and Yamagata prefectures shake as the earthquake struck on Tuesday night.

The hardest hit by the quake could not be contacted by telephone, according to public broadcaster NHK, which reported an evacuation order had been issued for Niigata city residents near the coast, telling them to move to higher ground.

One elderly man was injured after falling over during the tremor, and blackouts were reported in some areas including on major roads, NHK said.

All seven reactors at the Kashiwazaki-Kariwa nuclear plant in Niigata were off line and no abnormalities were reported.