Towns and farms around Sendai city in northern Japan have been engulfed by a seven-metre tsunami, while a four-metre wave swamped parts of Kamaishi on the Pacific coast.Residents have been ordered to high ground and stay away from the coast as tsunamis can strike in several waves.Seismologists say the quake was 160 times more powerful than the one that devastated Christchurch last month.
Japanese television has shown pictures of a wall of water kilometres wide moving its way across the countryside, engulfing everything in its path. The Cosmo oil refinery in Chiba prefecture outside Tokyo has exploded, sending flames dozens of metres into the air, with firefighters unable to contain the inferno. It is one of more than 40 blazes burning across Japan.
"An earthquake of this size has the potential to generate a destructive tsunami that can strike coastlines near the epicentre within minutes and more distant coastlines within hours," the agency said.
A tsunami warning has been issued across the wider Pacific including Russia, the territories of Guam, Taiwan, the Philippines, the Marshall Islands, Indonesia, Papua New Guinea, Nauru, Micronesia and Hawaii. Russia has evacuated 11,000 people from areas that could be affected, including Kuril islands and Sakhalin island. Hawaii has also ordered evacuations.The Bureau of Meteorology says there is no tsunami threat to Australia.
The quake, already considered one of the worst in Japan's history, struck about 382 kilometres north-east of Tokyo at a depth of 24 kilometres, the US Geological Survey said. The USGS reported at least eight strong aftershocks, including a 6.8 quake on the mainland 66 kilometres north-east of Tokyo.