Four dead in Japan 'quake

An earthquake with a magnitude of 6.8 and several powerful aftershocks rocked northern Japan yesterday, killing at least four people and injuring more than 400 while knocking out power and phone services, media said.

Several houses collapsed and a bullet train was partially derailed by the tremors centred in Niigata prefecture, a rural, mountainous area some 250 km north of Tokyo.

In addition, five people had been buried alive, Kyodo news agency reported, as aftershocks continued more than five hours after the initial jolt at 5.56 p.m. (0856 GMT).

That tremor, as well as aftershocks of up to magnitude 6.3, also shook buildings in Tokyo but there were no reports of injuries or damage in the capital.

At least four people were killed in the Niigata area, a rice-growing region on the Sea of Japan, while more than 400 had been injured, media reports said.

About 12,000 people had evacuated to schools and other public facilities in Nagaoka, a city of about 200,000, public broadcaster NHK said. Several fires broke out in the city but most were extinguished quickly, media said.

NHK said a landslide had buried three cars and Jiji news agency said an expressway tunnel had collapsed.

Two cars of the bullet train derailed near Nagaoka, but there were no injuries, a Transport Ministry official said.

The focus of the initial quake was about 20 km below the earth's surface.

The government set up a crisis centre in Tokyo, and officials said they were worried about more landslides in areas lashed recently by heavy rains.

Japan has been hit by a record 10 typhoons this year, including one that killed at least 80 people this week.

The quakes were the strongest to hit the region since 1933, officials said.

Some 278,000 homes were without power and telephone service was disrupted in some areas, making it difficult to contact ambulances to take the injured to hospital, media said.

Water and gas mains ruptured in some places.

Temperatures were falling and people who had gone outdoors for fear of further aftershocks were keeping warm with gas stoves and blankets, NHK said.

The Japan Meteorological Agency warned of more tremors.

"Aftershocks are continuing and we must be on alert for more," Japan Meteorological Agency official Masahiro Yamamoto told a news conference, adding that there had been about 120 tremors in the area detectable by humans.

The magnitude, a reading of energy released, was measured according to a Japanese technique similar to the open-ended Richter scale but adjusted for Japan's geological characteristics.

The defence ministry planned to dispatch patrol planes to the area to gather information and the National Police Agency put nearly 200 officers on standby for disaster relief, Kyodo said.

There were no reports of significant damage to industry in the area, which includes chemical and textile manufacturing as well as electronics and food processing.

Both Narita International airport near Tokyo and Haneda Airport in the capital were operating normally, officials said, and NHK said a nuclear reactor in Niigata was unaffected.

Japan is one of the world's most seismically active areas, with an earthquake occurring every five minutes.

The country accounts for about 20 per cent of the world's earthquakes of magnitude six or greater.

Memories are still vivid of the earthquake in the western city of Kobe which killed more than 6,400 people in 1995.

That quake measured 7.2 on the Richter scale.

The last quake of 8.0 or higher in Japan was in 1994.