An earthquake with a preliminary magnitude of 6.7 jolted islands off Japan's southernmost prefecture of Okinawa on Friday, the Japan Meteorological Agency said, but there were no immediate reports of injuries or damage.
A tsunami warning was issued for waves about 50cm, the agency said, adding that the waves were thought to have reached some shores already. The focus of the tremor was 40km below the seabed near the island of Miyakojima, 1900km southwest of Tokyo, the agency said.
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 6 or greater.
Tsunami warning in Japan after 6.7 quake - 20 Apr 2007 - NZ Herald: World / International News