Powerful 7.6-magnitude earthquake strikes Japan's northeast

TOKYO (Reuters) - A powerful 7.6-magnitude earthquake shook northeastern Japan late on Monday, prompting tsunami warnings and orders for about 90,000 residents to evacuate.

The Japan Meteorological Agency said a tsunami as high as 3 metres (10 feet) could hit Japan's northeastern coast after the earthquake struck off the coast at 11:15 p.m. (1415 GMT).

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.

The epicentre of the quake was 80 km (50 miles) off the coast of Aomori prefecture, at a depth of 50 km, the agency added.

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.

East Japan Railway suspended some services in the area, which was also hit by the massive 9.0-magnitude quake in March 2011. As of 1600 GMT, there was little information of major damage from public broadcaster 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.

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.

The yen weakened against major currencies after news of the tremor, before regaining some ground. The dollar touched a session high and was trading at around 155.81 yen around 1533 GMT, while the euro also hit a session high.

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% 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 tsunami 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.