Second deadly quake hits Japan, "race against time" to find survivors

* Japan PM warns of damage over wide area

* Auto, electronics factories halt production

* At least 26 killed in latest shock, some trapped

* No irregularities reported at nuclear facilities in area

* Tsunami advisory lifted, bad weather forecast (Adds NHK report on evacuation orders)

By Shinichi Saoshiro and Kiyoshi Takenaka

TOKYO, April 16 (Reuters) - Japanese rescuers were digging through the rubble of buildings and mud on Saturday to reach dozens believed trapped after a powerful 7.3 magnitude earthquake struck a southern island, killing at least 32 people and injuring about a thousand.

The shallow earthquake hit in the early hours, sending people fleeing from their beds on to dark streets, and followed a 6.4 magnitude quake on Thursday which killed nine people in the area. Rain and cold were forecast overnight, adding extra urgency to the rescue effort.

Television footage showed fires, power outages, collapsed bridges, a severed road hanging over a ravine and gaping holes in the earth. Residents near a dam were told to leave because of fears it might crumble, public broadcaster NHK said.

NHK said about 150,000 people in total across the affected region had received evacuation orders amid fears that heavy rain could trigger more landslides as the two quakes have made the ground unstable.

"I felt strong shaking at first, then I was thrown about like I was in a washing machine," said a Tokai University student who remains isolated in the village of Minamiaso in Kumamoto province on the island of Kyushu.

"All the lights went out and I heard a loud noise. A lot of gas is leaking and while there hasn't been a fire, that remains a concern," the student, who is sheltering in a university gym with 1,000 other students and residents, told Japanese media.

Many frightened people wrapped in blankets sat outside their homes while others camped out in rice fields in rural areas surrounding the main towns. About 422,000 households were without water, and about 100,000 without electricity, the government said. Troops were setting up tents for evacuees and water trucks were being sent to the area.

The National Police Agency said 32 people were confirmed dead. The government said about 190 of those injured were in serious condition.

"RING OF FIRE"

Heavy rain and wind were forecast, with temperature expected to drop to 13 degrees Celsius (55 degrees Fahrenheit) overnight. Firefighters handed out tarpaulins to residents so they could cover damaged roofs.

"The wind is expected to pick up and rain will likely get heavier," Prime Minister Shinzo Abe told a government meeting. "Rescue operations at night will be extremely difficult ... It's a race against time."