JAPAN: An earthquake measuring 5.4 on the open-ended Richter scale jolted people awake in Tokyo early today, but there were no reports of serious injuries or damage.
The focus of the pre-dawn quake was 40km (25 miles) north of the city, close to the capital's international airport, but flights were not affected, officials said. There was no impact on nuclear power plants in the area, authorities said.
"The shaking from side to side lasted for about 20 to 30 seconds," said a reporter for public broadcaster NHK, speaking form Tsukuba, north-east of Tokyo.
"There seems to be no visible damage," the reporter added.
The quake, which struck at 4:46 a.m. (1946 GMT), was measured by the Japan Meteorological Agency according to a technique similar to the Richter scale but adjusted for Japan's geological characteristics.
Earthquakes are common in Japan, one of the world's most seismically active areas. The country accounts for about 20 per cent of the world's earthquakes of magnitude six or greater.
In October 2004, an earthquake with a magnitude of 6.8 struck the Niigata region in northern Japan, killing about 40 people and injuring more than 3,000. That was the deadliest quake since a magnitude 7.3 tremor hit the city of Kobe in 1995, killing more than 6,400.