Oct. 7 (Bloomberg) -- Tokyo buildings shook as a magnitude- 5.7 earthquake hit close to the south coast of Honshu, Japan's main island, just before midnight yesterday, according to measurements by the U.S. Geological Survey's quake center.

The quake was centered about 20 miles (32 kilometers) northeast of Tokyo, geophysicist Waverly Person said by telephone from the center, in Colorado. The temblor hit at 11:40 p.m. in the Japanese capital.

An advisory from the U.S. center described the quake as ``moderate.''

The magnitude was revised by the U.S. from a preliminary reading of 5.8 taken less than 20 minutes after the event. The temblor happened about 36 miles below the surface.

East Japan Railway Co. briefly halted all trains in Tokyo, while other lines operated at reduced speeds, Japan's Kyodo news service reported.

Tokyo Electric Power Co. said there were no problems at its nuclear-powered plants in Ibaraki prefecture, where the quake occurred, Kyodo reported.

There was no danger of tsunamis, or giant waves caused by earthquakes, Japan's meteorological agency told the Associated Press.

To contact the reporter on this story: Todd Zeranski in New York at tzeranski@bloomberg.net

Last Updated: October 6, 2004 12:47 EDT