Tsunami alert issued after 8.8-magnitude quake strikes off the northeastern coast of the country.
A massive earthquake has struck off the northeastern coast of Japan, triggering a six-metre tsunami warning.
The US Geological Survey upgraded to 8.8 the magnitude of the earthquake that shook buildings in the capital,Tokyo, for several minutes on Friday, and sent people out onto the streets. Authorities had initially verified a magnitude of 7.9.
The news agency AFP said multiple injuries, but no immediate deaths, were reported from the Pacific coastal area of Miyagi on the main Honshu island.
Japan's NHK television showed black smoke billowing from a building in Odaiba, a suburb of Tokyo.
tremors were felt as far away as in the Chinese capital, beijing.
The country's meteorological agency warned that a tsunami as high as six metres could strike the coast near Miyagi prefecture, closest to the epicentre, and just a short time later broadcaster NHK said a tsunami of 50 cm had hit Japan's northern coast.
NHK showed pictures of major tsunami damage in the north, with cars, trucks, houses and buildings being swept away in Onahama city in Fukushima prefecture.
Russia, Marcus Island and the Northern Marianas are all being warned to expect a tidal wave as high as six metres.
Yukiko Shimahara, a Japanese journalist, told Al Jazeera that the airports and trains in Tokyo have been shut down following the quake.
Friday's quake struck at a depth of 24 kilometres, about 125 kilometres off the eastern coast, the meteorological agency said.
Japan lies on the "Ring of Fire"- an arc of earthquake and volcanic zones that stretches around the Pacific Rim and where about 90 per cent of the world's quakes occur.
Several earthquakes have hit the region in recent days, including a 7.2-magnitude quake on Wednesday.
http://english.aljazeera.net/news/asia-pacific/2011/03/2011311607470826.html 