A powerful 7.1 magnitude aftershock has rocked a large portion of eastern Japan, less than four weeks after an even stronger quake left thousands of people dead and caused a nuclear power disaster.
Japanese television is warning of a possible tsunami and for people living next to the coast to move immediately to higher ground. NHK also told people to stay away from buildings that were damaged by the 9.0 earthquake on March 11.
The earthquake was centered under the Pacific Ocean off Japan's eastern coast, in the same general area as last month's earthquake and tsunami, which killed more than 12,000 people and has left more than 14,000 missing.
