A strong aftershock ripped through northeastern Japan, killing at least two people, injuring more than 100 and piling misery on a region still buried under the rubble of last month's devastating tsunami.
The aftershock late Thursday was the strongest tremor since the March 11 monster quake and did some damage, but it did not generate a tsunami.
The Fukushima Dai-ichi complex — where workers have been frantically trying to cool overheated nuclear reactors since they lost cooling systems last month — appeared to have been spared and reported no new abnormalities.
Water spilled from another nuclear facility, the Onagawa plant in northeast Japan, but there was no change in radiation levels outside the plant, Tohoku Electric Power, the operator of the plant, said Friday.
It said water sloshed out of spent fuel pools in the plant's No.1, No.2 and No.3 reactors, which had been shut down after the 9.0 magnitude quake on March 11, and had also leaked in three other locations in the No.3 reactor complex.
Thursday's 7.1-magnitude quake knocked out power to much of the area.
Many people in the area have lived without water and electricity for nearly a month, and the latest tremor sunk more homes into blackness: In total, around 3.6 million households — about 60 percent of residents in the area — were dark Friday, said Souta Nozu, a spokesman for Tohoku Electric, which serves northern Japan.
Matsuko Ito, who has been living in a shelter in the small northeastern city of Natori since the tsunami, said there's no getting used to the terror of being awoken by shaking.
"I was almost as scared as much as last time," said the 64-year-old while smoking a cigarette outside. "It's enough."
She said she started screaming when the quake struck around 11:30 p.m.
"Something has changed," she said. "The world feels strange now. Even the way the clouds move isn't right."
Thursday's quake initiated a tsunami warning of its own, but it was later canceled. Two people were killed, fire department spokesman Junichi Sawada reported Friday. A 79-year-old man died of shock and a woman in her 60s was killed when power was cut to her oxygen tank. More than 130 people were injured, according to the national police agency.
The temblor's epicenter was in about the same location as the original 9.0-magnitude tremor, off the eastern coast and about 40 miles (65 kilometers) from Sendai, an industrial city on the eastern coast, according to the U.S. Geological Survey. It was strong enough to shake buildings for about a minute as far away as Tokyo, about 200 miles away.
At a Toyota dealership in Sendai, most of a two-story show window was shattered, and thick shards of glass were heaped in front of the building. Items fell off store shelves and a large automated teller machine crept across the floor at a FamilyMart convenience store.
Police directed cars through intersections throughout the city on Friday because traffic lights were out. Small electrical fires were reported.
While the city is far enough inland that it largely escaped tsunami damage, people there lived without regular services for weeks. Within an hour of Thursday's quake, they rushed convenience stores and cleared shelves of ice, water and instant noodles — items that were in short supply after the bigger quake.
The operator of the tsunami-ravaged Fukushima Dai-ichi plant said there was no sign the aftershock had caused new problems there. Workers briefly retreated to a quake-resistant shelter in the complex and suffered no injuries.
After the March 11 quake knocked out power in the region, the wave flooded the plant's diesel generators, leaving the complex without any electricity. Workers have been struggling to stem a tide of radiation since, using makeshift methods to pump cooling water into the reactors. That work continued uninterrupted after the latest quake, according to Japan's Nuclear and Industrial Safety Agency.
Other facilities along the northeastern coast remained connected to a power source Friday, and the agency said they were all under control. Backup generators kicked in at two — Rokkasho and Higashidori.
At a third north of Sendai — which has been shut down since the tsunami — one of three power lines was supplying electricity, and radiation monitoring devices detected no abnormalities. The Onagawa power plant's spent fuel pools briefly lost cooling capacity, but it resumed because a power line was available for electricity.
"It's the way it's supposed to work if power is lost for any reason," said David Lochbaum, director of the nuclear safety project for the U.S.-based Union of Concerned Scientists.
Also Friday, Toyota said it will resume production at all of its 18 Japan plants from April 18 to 27. The world's No.1 automaker said the plants will operate at limited capacity due to parts shortages.