A nurse survived eight days in the wreckage of a Turkish hospital destroyed by an earthquake in 1992. A newborn was rescued after more than a week in the rubble of Mexico City's 1985 quake. Now, in China, rescuers are pulling out victims days after they were buried by a powerful earthquake.

How long can people survive trapped under piles of rubble?

A week or more under the best circumstances, some experts say. That means the victim isn't seriously hurt, was in good condition to begin with and the weather isn't too hot or too cold.

Survival can depend on all of those things.

"The stronger the person was prior to being trapped or injured, the better the chances for survival," said Dr. Paul Auerbach, who teaches emergency medicine at Stanford School of Medicine and is the editor of a book on wilderness medicine.

On Friday, four days after a powerful quake struck central China, rescuers freed a nurse from the debris of a clinic in Beichuan county, the official Xinhua news agency reported.

"It really depends on the condition of the patient," said Dr. Irving "Jake" Jacoby of the University of California, San Diego. He heads a medical team that responded to the 1989 Loma Prieta quake in California, Hurricane Katrina and other disasters.

Those who are trapped but relatively uninjured could survive for a week or even 10 days, and in extreme circumstances two weeks or more, he said. However, the vast majority of rescues usually occur in the first 24 hours after a disaster, he said. After that, the chances of survival drop as each day passes.

Infants and the elderly are the most vulnerable, Jacoby said. Even so, there were several newborns pulled from the rubble days after Mexico's 1985 quake.

In China, the situation is getting more dire as time passes.

"Now that we're days after the earthquake, people who sustained serious injuries that caused severe organ damage or bleeding would not survive," Auerbach said.

Access to water is more important than food for those trapped for days. Continued...