The Japanese Meteorological Agency (JMA) on Monday reported a 7.6 magnitude earthquake off the coast of its eastern Aomori prefecture.

The JMA reported that the epicentre of the quake was registered off the coast of Aomori at a depth of 80 kilometres at 11:15pm local time (7:15pm PKT).

On Japan’s 1-7 scale of seismic intensity, the tremor registered as an “upper 6” in Aomori prefecture — a quake strong enough to make it impossible to keep standing or move without crawling.

In such tremors, most heavy furniture can collapse and wall tiles and windowpanes are damaged in many buildings.

Tsunami warnings were issued for the prefectures of Hokkaido, Aomori and Iwate, and tsunamis from 20 to 70 cm (7 to 27 inches) high were observed at several ports, JMA said.

Japanese public broadcaster NHK World reported that a tsunami warning had been issued 10 minutes later, urging citizens along the northeast coast to evacuate. Waves were estimated to reach a height of three metres.

There have been no reports of casualties, but NHK reported that “abnormalities at nuclear power plants and other facilities in various locations” are being examined.

No irregularities were reported at nuclear power plants in the region run by Tohoku Electric Power and Hokkaido Electric Power, the utilities said. Tohoku Electric initially said thousands of households had lost power, but later lowered that number to the hundreds.

East Japan Railway suspended some services in the area, but as of 9pm PKT, there was little information on major damage from NHK.

“There is a possibility that further powerful and stronger earthquakes could occur over the next several days,” a JMA official said at a briefing.

The yen weakened against major currencies after news of the tremor, before regaining some ground.

Japan is one of the world’s most earthquake-prone countries, with a tremor occurring at least every five minutes.

Located in the “Ring of Fire” of volcanoes and oceanic trenches partly encircling the Pacific Basin, Japan accounts for about 20 per cent of the world’s earthquakes of magnitude 6.0 or greater.

The northeastern region suffered one of the country’s deadliest earthquakes on March 11, 2011, when a 9.0-magnitude tremor struck under the ocean off the coast of the northern city of Sendai.

It was the most powerful ever recorded in Japan and set off a series of massive tsunamis that devastated a wide swathe of the Pacific coastline and killed nearly 20,000 people.

The 2011 tsunami also damaged the Fukushima Daiichi nuclear plant, leading to a series of explosions and meltdowns in the world’s worst nuclear disaster for 25 years.