By CARA RUBINSKY, Associated Press – 24 mins ago

TOKYO – A magnitude-7.4 aftershock rattled Japan on Thursday night, knocking out power across a large swath of the northern part of the country nearly a month after the devastating earthquake and tsunami that flattened the northeastern coast.

Japan's meteorological agency issued a tsunami warning but canceled it about 90 minutes later. Officials said power was out in all of three northern prefectures (states) and in parts of two others.

There were no immediate reports of serious injuries or damage. The aftershock was the strongest since the March 11 megaquake and tsunami that killed some 25,000 people, tore apart hundreds of thousands of homes and caused an ongoing crisis at a nuclear power plant.

The operator of the tsunami-ravaged Fukushima Dai-ichi nuclear plant said there was no immediate sign of new problems caused by the aftershock, and Japan's nuclear safety agency says workers there retreated to a quake-resistant shelter in the complex. None were injured. The crisis there started when the tsunami knocked out cooling systems. Workers have not been able to restore them.

Thursday's quake knocked out several power lines at the Onagawa nuclear power plant north of Sendai, which has been shut down since the tsunami. One remaining line was supplying power to the plant and radiation monitoring devices detected no abnormalities. The plant's spent fuel pools briefly lost cooling capacity but an emergency diesel generator quickly kicked in.

Officials said the aftershock hit 30 miles (50 kilometers) under the water and off the coast of Miyagi prefecture. The U.S. Geological Survey in Golden, Colo., later downgraded it to 7.1.

Buildings as far away as Tokyo shook for about a minute.

The quake struck at 11:32 p.m. local time. Moments beforehand, residents in the western Tokyo suburb of Fuchu were warned on a neighborhood public address system of an imminent quake.

In Ichinoseki, inland from Japan's eastern coast, buildings shook violently, knocking items from shelves and toppling furniture, but there was no heavy damage to the buildings themselves. Immediately after the quake, all power was cut. The city went dark, but cars drove around normally and people assembled in the streets despite the late hour.

Prime Minister Naoto Kan huddled with staff members in his office shortly afterward, according to deputy Cabinet spokesman Noriyuki Shikata.


there was also a 6.5 mag in mexico also, but no details yet...