Japan is considering creating a back-up capital city in case a major natural disaster strikes Tokyo.
The Ministry of Land and Infrastructure will consider the possibility of moving some of Tokyo's capital functions to another big city, like Osaka.
Japan is located on the junction of four tectonic plates and experiences one-fifth of the world's strongest earthquakes.
Geologists have warned that Tokyo is particularly vulnerable to powerful earthquakes.
It is feared that if another Great Quake like the magnitude 9.0 on 11 March struck Tokyo, it could destroy the country's political and economic base.
The European Space Agency says the tsunami on 11 March caused waves that hit an ice shelf in Antarctica 13,000km away, smashing parts of it into huge icebergs.
The agency says the largest berg that broke from the Sulzberger ice shelf
measured about 9.5km by 6.5km, with a likely depth of about 80 metres.
However, analysis of radar pictures in the United States suggests that the waves were probably only about 30 cms high by the time they had crossed 13,000km of ocean.