Earthquake shakes buildings in Tokyo, but no tsunami warning

An earthquake with a preliminary magnitude of 4.7 shook buildings in Tokyo on Wednesday, Japan's Meteorological Agency said, but no tsunami warning was issued and there were no immediate reports of damage.

Earthquakes are common in Japan, one of the world's most seismically active areas. Japan accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater.

On March 11, 2011, the northeast coast was struck by a magnitude 9 earthquake, the strongest quake in Japan on record, and a massive tsunami. Those events triggered the world's worst nuclear crisis since Chernobyl a quarter of a century earlier.