Another strong quake sparks tsunami alert in Japan

A strong earthquake rattled Japan's northeast coast and sparked a fresh tsunami alert, one month after the worst ever natural disaster devastated the country.

The 7.1-magnitude aftershock briefly forced Tokyo's main international airport to close both of its runways. The epicentre was just inland and about 100 miles north of Tokyo.

The operator of the crippled Fukushima nuclear complex said the latest quake had no impact on the plant, Telegraph reports.

External electrical supplies to some areas of the plant were disrupted and work to pump in cooling water to its overheating reactors suspended.

 However, Hidehiko Nishiyama, a spokesman at the Japan Nuclear and Industrial Safety Agency, said the supply of electricity had been restored about 50 minutes after the earthquake.

The initial view of staff at the head office of Tokyo Electric Power, the operator of the Fukushima Daiichi nuclear plant, was that the outage was unlikely to have any safety implications, Mr Nishiyama said, Financial Times informs.