TOKYO, April 17 (Reuters) - An earthquake with a

preliminary magnitude of 6.4 hit southern Japan late on

Wednesday, the Japan Meteorological Agency said.

The epicentre of the earthquake was the Bungo Channel, a

strait separating the Japanese islands of Kyushu and Shikoku,

the agency said, adding that no tsunami warning had been issued.

Ehime and Kochi prefectures were hit by the quake with an

intensity of 6 on Japan's 1-7 scale, the JMA said.

No major damage has been reported so far, according to

local media reports.

The Ikata nuclear plant in Ehime prefecture, where one

reactor is in operation, reported no irregularities, operator

Shikoku Electric Power said, according to public

broadcaster NHK.

Earthquakes are common in Japan, one of the world's most

seismically active areas. Japan accounts for about one-fifth 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.