When an earthquake strikes a town, or a building is levelled by an explosion, news footage invariably shows search and rescue teams trawling through the rubble looking for survivors. But what does it take to rescue people trapped under tons of concrete?
Step one - coordination
The first thing is to activate search and rescue teams, often highly trained volunteers.
"Most of our members are doctors, ambulance operators, engineers or fire fighters," said John Holland, operations director of Rapid UK, a charitable search and rescue group.
They go through a rigorous two-year training process before they are allowed to assist in disasters.
"We try to deploy within 24 hours because the earlier we are on the ground, the better the chances of rescuing survivors," Holland said. "During the Pakistan earthquake [in 2005], we were able to deploy in 21 hours."
The International Search and Rescue Advisory Group (INSARAG) - a global network of more than 80 countries and disaster response organizations under the UN umbrella - has standardized guidelines for rescue missions.
"Once a government has made that call for international assistance, we alert our members, who begin mobilizing to travel to the area," said INSARAG's Winston Chang, a Singapore Civil Defence Force veteran who coordinated the search and rescue efforts following the recent earthquake in Padang, Indonesia. "We run a portal where once a disaster occurs, we pool information and our various teams can input data on their movements - whether they are on standby, mobilizing or have reached the ground."
INSARAG will usually set up an “on site operations coordination centre” where all search and rescue teams get instructions - depending on their area of specialty - on where to go and how to operate; the desk holds regular meetings to update itself and the teams on the progress being made on the ground.
"These operations can be quite large; just now in Padang, there were a total of 21 teams with 668 personnel and 67 search dogs," Chang said. "They need bases of operation where they will fuel their heavy equipment, coordinate their internal logistics and sleep."
"We also ensure that they follow specific standards of operation and remain culturally sensitive, especially since the teams are from such diverse backgrounds," he added.
Once in the disaster area, the first step is to analyze the task at hand, said Julie Ryan, a volunteer with the British NGO, the International Rescue Corps.
In a collapsed building, "you need to analyze the building, assess its history and try to establish where in the building people are most likely to be", she told IRIN. "You also need to determine how badly a building has been damaged and whether it is likely to collapse any further, causing damage to [survivors] and rescue teams."
Photo: Jefri Aries/IRIN
|A survivor in her home, which was razed to the ground by the recent earthquake in western Sumatra, Indonesia|
The assessment also involves checking for hazards such as downed power lines, gas leaks, flooding and hazardous materials. Protective gear includes special suits, gloves, masks, and oxygen and carbon monitoring systems for air quality.
Step three - search mode
At its most basic, this involves trying to spot limbs in the rubble, and calling out to survivors to identify their locations.
Rescuers look for "voids", or pockets where people may be trapped when walls collapse or where survivors may have hidden, such as under desks, in bath tubs or stairwells.
"We feed a camera on the end of a flexible pole into the collapsed building - this shows where people are and how much of the building's structure is left," Ryan said.
"Rescuers also use sound location devices connected to a microphone system; the device bangs on the rubble three times and if people tap back or call out for help, they can be tracked and assisted," she added.
Listening is a crucial part of the operation, and search teams will often stop for several minutes to try to hear any calls, scratches or taps.
Other search tools include a thermal image camera system, which shows areas of body heat, and trained sniffer dogs. "We also use a carbon dioxide analyzer, which helps us detect people who might be unconscious but still breathing," Ryan said.
Buildings that have been searched are marked with INSARAG-recognized signs to avoid duplication of searches.
As survivors are found, rescuers try to get them to keep talking to determine their exact location, and dig towards them - the least dangerous way to do this is by hand.
Step four - the rescue operation
If survivors are trapped under rubble, it may need to be stabilized first; a process called cribbing - the construction of a rectangular wooden framework, a box crib, underneath the debris - may be used.
Survivors who are not able to move usually need to be lifted, dragged or carried out of the rubble using special equipment.
"If people cannot be manually dug out, then we can cut them out - there are specialized tools that can cut through concrete, metal and wood to reach survivors," Ryan said. "There is also a process known as 'slabbing', where heavy slabs of concrete are removed in order to free survivors - this is always a very difficult judgment call, because it risks further collapse, which could injure or kill more people."
Concrete saws, jackhammers, chainsaws, bolt cutters, cranes and bulldozers are all part of the tool kit; chains, cables, anchors and rope-hauling systems are used to remove large pieces of masonry. Other equipment may include flat bags that are inserted under heavy objects and inflated with an air pump, and “shoring” equipment, which ensures passageways are stable and safe.
As survivors are removed, their medical condition is determined; patients are prioritized according to triage - based on the severity of their condition.
Search and rescue teams usually start the most urgent medical procedures on site; the most experienced teams may have defibrillators and endo-tracheal equipment to shock people back to life or perform emergency tracheotomies.
Step five - closure
Deciding when to end a rescue operation is always difficult.
"Obviously, the more time passes the less likely you are to find people alive," said Ryan. "But sometimes - especially if they have water available - people can remain alive for many days. In Pakistan, our team rescued two boys five days after the earthquake; they had survived on trickles of rainwater through the rubble."
According to Ryan, finding bodies - cadaver rescue - after the search for survivors is over is a very important part of any operation.
"Even when people haven't survived the collapse of a building, families find that having a body to bury is an important part of getting closure," she said.
According to INSARAG's Chang, the high octane operations can take their toll on rescuers, especially when they have to pull hundreds of dead people out of buildings.
"Most of them are used to dealing with blood and death in their daily professions, but from time to time it can become very difficult," he said. "Many teams are equipped to deal with trauma - the Swiss government's team, for instance, has a psychologist on hand, while doctors in the Singapore team have been trained to search for signs of trauma in team members."
Once the host government officially calls off the search, INSARAG starts the process of withdrawing the teams. A few remain and become part of the humanitarian relief effort, rebuilding hospitals and schools or shelter for families, but most will head back to their day jobs and await the next call to action