MINAMI SOMA, Japan  - The Odaka neighborhood seems frozen in time since it was abandoned after the tsunami nearly a month ago: Doors were left hanging open and bicycles were abandoned. A lone taxi sits in front of the train station. Mud-caked dogs roam empty streets, their barking and the cawing of crows the only sounds.

Many homes and businesses in the area escaped serious damage from the March 11 earthquake and tsunami, but their owners have not been allowed back because of concerns about radiation from the nearby nuclear plant crippled by the massive wave.

Some have returned anyway, saying they need to get on with their lives.

"It's eerie here," said Masahiko Sakamoto, 59, who was loading a truck with two other workers Thursday in their company's parking lot. "Everyone has gone. I think the number of people who have stayed is just about zero. Some people come back during the day. But it's too scary at night."

It was the third time Sakamoto, a supervisor, has violated the order to stay out of a 12-mile (20-kilometer) zone around the Fukushima Dai-ichi plant. His home is in the evacuation zone too, so he's living in a shelter where he gets screened for radiation every day.

He knows it could be dangerous to go to work, but says the small company that makes cylinders for heavy machinery will go broke if it can't get back to business soon. He believes the shop could be repaired in a week, but not as long as radiation fears persist.

Government officials have said it is important that the 70,000 to 80,000 people living in the zone stay away, but there are few roadblocks, and police are occupied with other duties and have, for the most part, not been forcing people out.

Some never left.

"I'd rather die from radiation than live in a shelter," said 55-year-old Mitsuo Sato, who has food and electricity at his home in the evacuation zone but was riding his bike to get water from a well. "I don't think the police know I'm here."

A scary, fresh reminder of the March 11 disasters occurred late Thursday night, when a 7.1-magnitude aftershock struck off the coast in roughly the same area as last month's 9.0 quake. A tsunami warning was issued, but later canceled.

Elsewhere in Minami Soma, a city of 71,000 where Odaka is located, officers in white and blue protective suits were working with troops to search for the bodies of nearly 1,100 missing residents. Nearly 400 have been confirmed dead.

Last month's disasters may have killed as many as 25,000 people, but only 12,600 bodies have been found. High levels of radiation often have forced searchers to retreat.

"I believe the search will continue until they find as many of the missing as they can, but we fear many of the missing were washed out to sea or are buried under rubble," said Takamitsu Hoshi, a Minami Soma official.

Some of Minami Soma lies outside the evacuation zone, such as around city hall, where things are rapidly returning to normal and many shops and restaurants have reopened. Supplies are flowing in after the mayor made a plea for help in a YouTube video. Still, more than half of the city's residents have left.

Odaka is in the southeast part of the city, about 11 miles (18 kilometers) from the nuclear plant, where workers have been frantically trying to restore reactor cooling systems crucial to stopping the release of radiation into the air and water.

Recent progress appears to have slowed the contamination. Radiation levels in waters off the coast have fallen dramatically since workers plugged a leak gushing directly into the Pacific Ocean, although contaminated water continues to pool throughout the complex, often thwarting work there. A floating island storage facility meant to hold the water arrived at the port near Tokyo on Thursday and will soon head to Fukushima.

Technicians are in the midst of a six-day operation to pump nitrogen into containment chambers around three troubled reactors to prevent hydrogen explosions, three of which rocked the complex in the days right after the tsunami.

Plant operator Tokyo Electric Power Co. has been under intense pressure to get the crisis under control, and the company's president was hospitalized last week amid reports he'd had a breakdown. Masataka Shimizu spent eight days in the hospital with dizziness and high blood pressure, but was back at work Thursday, according to spokesman Takashi Kurita.

There has also been pressure from some evacuees to allow them to at least go back to their homes long enough to retrieve possessions.

Chief Cabinet Secretary Yukio Edano said the government is studying ways to allow people to return briefly, but they would have to be escorted and wear protective gear.

"I understand that many residents have eagerly waiting for a chance to go back, but this is not something we can approve just to mark one month from the disaster," Edano said. "If we provide an opportunity, we cannot allow anyone to go anytime."

The government also has said it might expand the evacuation zone due to concerns about longer-term radiation exposure.

The village of Iitate, about 25 miles (40 kilometers) from Fukushima Dai-ichi, said Thursday it is advising pregnant women and children under 3 to go to hotels farther from the plant. The International Atomic Energy Agency last month reported high levels of contamination in Iitate's soil, but village officials did not say why they are just now suggesting some people leave.

For Sato, the Odaka resident who has stayed in the evacuation zone, concerns about living conditions outweigh fears about radiation.

"It's cold in the shelters, and I don't want to live on a gymnasium floor," he said.

"I just don't want to leave," he added. "But I'm here alone. It feels strange living in an empty town."

Associated Press writers Shino Yuasa and Mari Yamaguchi in Tokyo and Matthew Daly in Washington also contributed.