Earthquake off Japan triggers tsunami alert

TOKYO (Reuters) - A strong earthquake struck Sunday in the same region of northern Japan was hit by a massive earthquake in March, but there was no sign of further damage along the coast or in the factory Fukushima crippled nuclear power, officials said.

The Japan Meteorological Agency lifted a tsunami warning for the area before noon after initially urging residents in the affected area to stay away from the coast.

The U.S. Geological Survey estimated the quake at magnitude 7.0 and said it had occurred at a depth of 18 km (11 miles) off the northern coast of Japan, just before 10 o'clock local time.

Four months ago, the same region was hit by a massive earthquake and tsunami that killed at least 21,000 dead or missing. The disaster of March 11 cut power plant in Fukushima and triggered a crisis of radiation.

"It started as a small side-road shake, then gradually grew stronger," said Nobuyuki Midorikawa, an official at the Iwaki City, Fukushima.

"Having experienced the devastation of much of Mars, the latter earthquake and tsunami warning made me feel that we can not let our guard against tsunamis," said Midorikawa.

Tokyo Electric Power said workers close to the central coast of Fukushima were briefly evacuated to higher ground before returning to work.

The utility said there was no immediate sign of further damage to the nuclear plant where workers have struggled to maintain a cooling system to stabilize the improvised operating reactors and radiation control. The cooling system was not interrupted by the earthquake, the company said.

Tokyo Electric said there was also no damage to the massive barge moored just off the Fukushima nuclear power plant that was used as a deposit for temporary storage of water radiated for any damage.

The March 11 earthquake that struck the coast of northeastern Japan had a magnitude of 9.0 and triggered a tsunami that caused extensive damage along the coast and was about 14 meters in the nuclear power plant in Fukushima .

The power loss in the Fukushima nuclear plant released cooling systems and fuel brought in three of the six reactors at the plant to melt. Subsequent explosions of hydrogen scattered radioactive debris over a wide area.

About 80,000 inhabitants in the vicinity were forced to evacuate due to the radiation and the Government of Japan has been criticized for his handling of the disaster, putting pressure on unpopular Prime Minister Naoto Kan to resign.

A concern was the strength to support the building that remains of reactor No. 4 in Fukushima, and a spokesman for Tokyo Electric said the utility expected to hold the structure in an earthquake stronger than that hit Sunday.