How people survive for days under earthquake rubble as survivors are found in Turkey, Syria

Days after a 7.8-magnitude earthquake and hundreds of powerful aftershocks struck southeastern Turkey and northwestern Syria, survivors were still being pulled from the rubble.

Rescue efforts continue even as the death toll has surpassed 41,000 as of Wednesday afternoon.

Although most rescues happen in the first 24 hours after a natural disaster, experts said people can survive up to a week or more trapped under fallen debris depending on several factors including whether they have access to water and air, weather conditions and the extent of their injuries.

"A natural disaster is something that leaves us all feeling helpless, in general, just by virtue of what it is," Dr. Emanuel Maidenberg, a clinical professor of psychiatry at the University of California, Los Angeles, told ABC News. "It's unpredictable and uncontrollable and, as human beings, we all have to accept that reality of it and the uncertainty that is associated with not knowing when and how intense it could happen."

He added, "We're mostly not spending days anticipating or waiting for events of that kind. And yet, when it happens, there are other mechanisms that become available to us."

Make noise

Dr. Stephen Morris, an associate professor in the department of emergency medicine at UW Medicine with international disaster-response experience, told ABC News one of the best ways to help yourself be rescued is to find some way to communicate with the outside world that you're still alive.

That means screaming or making noise to alert emergency rescue workers to your location.

"The really only thing that's sort of paramount to express is that being found is really the only way of survival," he said. "And so, finding a way to communicate, making repetitive noise, this usually involves some sort of tapping against the infrastructure where people are trapped."

He said, in past earthquakes, survivors have even managed to obtain cell service and are able to call or text to let people know they are in need of rescue.

"Getting the message that you're there and you're still alive out is what gets people rescued," Morris said.

He also stressed that people should try to protect their airways if they are trapped, whether that means making as much room for themselves and keeping objects out of their face.

Importance of drinking water

When people have survived for several days, it's usually because they have access to fresh drinking water, Morris said.

Although a person can survive without water for about one week, he said being close to water supply when being trapped is the best chance of survival, although this is often a matter of luck.

"There's a lot of luck involved with the people that have survived for very long periods of time," Morris said.

A 17-year-old boy named Muhammet Korkut told ABC News he survived while trapped for 94 hours by drinking his own urine.

Morris said he advises against this if you're trapped under rubble -- as well as drinking sea water or alcohol -- because it can be dehydrating.

"Almost universally not recommended," he said. "It can absolutely dehydrate you faster than not drinking anything at all. There's definitely a psychological event that occurs where people are so desperately thirsty that any liquid will seem preferable to nothing at all. But certainly, from a survival standpoint, these are not adequate."

Morris said if people absolutely need to drink some sort of liquid and are not near water but have access to soda or coffee, he recommends drinking it in extreme circumstances, as long as people realize that these liquids can still be dehydrating.

Korkut said he also ate his family's flowers to survive, which is something else Morris said he doesn't recommend.

"The idea that you need food to survive, that's just not the case," he said. "People can survive weeks and weeks, if not months, without eating. It's very unpleasant … but the majority of people will not die without eating."

Cold weather can play a factor

One thing that can affect survival is the weather. Currently, in Turkey, temperatures have been unseasonably cold.

Temperatures at night have fallen to as low as 32 F, making it hard for those who are trapped to stay warm. Morris said this is another example of how luck can play a role in survival.

"The inclement weather also plays a role," Morris said. "So, hypothermia will set in very quickly, in cold, especially when people are unable to access some way to cover themselves and to stay warm after events, and certainly that's compounded by injuries that they might have from the event itself."

Psychological survival mechanism activated

Maidenberg said several psychological and physiological mechanisms are activated when people are trapped under rubble or heavy debris.

The goal of these mechanisms is to help humans tolerate distress. Everybody has them, but they are not typically used because there is no need for them, he said.

"In these circumstances, we as human beings are able to activate mechanisms that are needed in order to survive," Maidenberg said. "It's a survival instinct that includes resilience and flexibility. Flexibility means being in a very uncomfortable -- physically and emotionally -- position for prolonged periods of time."

He added that people are able to withstand the discomfort or hardship of being trapped because the mechanism has kicked in of fighting for survival.

"Our will to survive and to live becomes the most important goal to pursue," Maidenberg said. "There's this sort of spiritual process of some kind, there's a physiological process of some kind, and physical process of some kind that, all together, come to help us to survive for as long as possible."

Fight-or-flight response

Maidenberg said the fight-or-flight response is also being activated when somebody is trapped under rubble or debris.

This is a psychological reaction that occurs in response to an event that is stressful, frightening or life-threatening. Because the option to flee no longer exists, people are now fighting to survive.

"It really very much has to do with our perception of danger or threat," he said. "So, if anything happens during the time, that the person stands in that circumstance that he or she interprets as becoming imminently dangerous, that activates that physiological response."

Maidenberg continued, "And in these circumstances, there is not much typically that the person can do. So, it becomes a matter of perseverance and distress tolerance."

Following a person being rescued, Morris said it's important to examine patients for any crush injuries and renal failure, especially if they haven't had water for days.

"People are dehydrated and the first thing to fail is their kidney," he said. "Additionally, people that have crush injuries, as the crushed tissue releases a lot of toxins, which then get filtered out through the kidney and damage the kidney."

Survivors may need IV fluids or dialysis to help flush toxins from the body when the kidneys aren't functioning properly. They may also need to be evaluated long-term to see if they develop kidney disease.

As for psychological help, Maidenberg recommends using social support or family support to being able to work through -- or talk about -- the experience.

"There are many different things that can be helpful that we have access to, and it depends on the environment and our own willingness to volunteer information," he said. "I think that personally, it's generally always helpful to be able to put emotional experiences into words and be able to describe it, including what happened and how it made us feel."

But he added that it may be different for other people, saying, "It depends on the specific circumstances and depends on one's need for other people's support and understanding. In general, it's considered to be very helpful, but it's not for everybody."