A 7.1 magnitude quake rocked Japan exactly a month after the devastating earthquake and tsunami.
Japan s meteorological agency warned that a one-metre wave could hit Ibaraki prefecture, one of the areas pummelled by last month s massive tsunami, before cancelling the alert less than an hour later. The epicentre was 81 kilometres south of Fukushima city, which was engaged in battling with the troubled nuclear plant.
Several commemoration ceremonies were being held in Japan when the country rocked again and a panic gripped the people.
Japan expanded the evacuation zone around its crippled nuclear plant because of high levels of accumulated radiation. The shocks caused off-site power supply for two damaged reactors to shut down.
Several thousands of people died and thousands of others went missing as a result of the worst natural disaster of the country that struck on March 11.