Quake hits southern Japan

A magnitude 7.3 earthquake has struck southern Japan, killing at least one person, injuring many more and bringing down buildings, local media report, just over a day after a quake killed nine people in the same region.

The authorities warned of damage over a wide area following the quake early on Saturday, as reports came in of people being trapped in collapsed buildings, fires and power outages.

Residents living near a dam were told to leave because of fears it might crumble, broadcaster NHK said.

Saturday's tremblor triggered a tsunami advisory, although it was later lifted and no irregularities were reported at three nuclear power plants in the area, a senior government official said.

People still reeling from Thursday's shock poured onto the streets after the Saturday quake.

Kyodo news agency said one person was confirmed dead. NHK reported that nearly 400 people were being treated in hospitals, but that figure included "people who don't feel well", so it was not clear how many serious injuries there were.

Media reported fresh damage, including collapsed buildings and roads. A fire erupted in a what appeared to be an apartment building in Yatsushiro city, while some people were trapped in a nursing home in the town of Mashiki, according to NHK.

The epicentre of the quake was near the city of Kumamoto and measured at a shallow depth of 10km, the US Geological Survey said. The entire city of 730,000 was without power.

Prime Minister Shinzo Abe, arriving at his office, told reporters the government was making every effort to determine the extent of the damage, carry out rescue and recovery, and to get accurate information to citizens.

"It's possible that there may be damage over a wide area," Abe said.

The earthquake on Thursday evening in the same region was of 6.4 magnitude and experts said the two tectonic events could be linked.

"Thursday's quake might have been a foreshock of this one," Shinji Toda, a professor at Tohoku University, told NHK.

Several aftershocks rattled the region later on Saturday, including two of nearly 6 magnitude, and the Meteorological Agency warned of more.

Television footage showed many frightened people wrapped in blankets sitting outside their homes.

The Japan Meteorological Agency initially said the Saturday quake was 7.1 magnitude but later revised it up to 7.3.

A magnitude 9 quake in March 2011, to the north of Tokyo, touched off a massive tsunami and nuclear meltdowns at Fukushima. Nearly 20,000 people were killed in the tsunami.