In Japan, an earthquake with a preliminary magnitude of 4(point)9 hit the Tokyo area today but no tsunami warning was issued.<br/><br/>Japan's Meteorological Agency said the quake was centred in northwestern Chiba prefecture, east to Tokyo. <br/><br/>According to the agency Japan is one of the world's most seismically active areas, accounting for about 20 per cent of the world's earthquakes of magnitude 6 or greater. <br/>