It’s the ultimate catastrophe: an atomic bomb attack on a populated area. What should you do in an emergency if you are inside a building during the explosion? Researchers from Cyprus calculate where the chances of survival are highest.
The possibility of a nuclear strike has been discussed in public again since the Russian war of aggression against Ukraine. One thing is certain: when a nuclear bomb goes off, there is no good place to be in the immediate vicinity. Because anything that is too close to the fireball vaporizes immediately. And the intense radiation is dangerous even from a distance. The explosion also creates a massive pressure wave. Through them, the air reaches speeds strong enough to cause serious injury to humans.
But what if you stay indoors? Researchers from the University of Nicosia in Cyprus wanted to find out how a nuclear blast would affect people inside buildings. To do this, they simulated the explosion of a typical ICBM with an explosive force of 750 kilotons – which corresponds to 750,000 tons of the explosive TNT. They published their results in the journal “Publication Physics of Fluids”.
The effects in the “Moderate Damage Zone”, i.e. an area with moderate damage from the blast wave, were examined. In this, the force of the air masses is sufficient to bring down some buildings and injure people who are outdoors. However, sturdier concrete buildings can withstand in this area. And that’s what the researchers wanted.
Using sophisticated computer models, the scientists tested how a nuclear pressure wave would travel through a building that was still standing. The simulated building structure contained rooms, windows, doors and corridors. In the model, the velocity of the air at different locations in the building was calculated to determine where people are best and least protected from the blast wave.
“Before our study, the danger to people in a concrete building that withstands the blast was unclear,” said author Dimitris Drikakis, according to a statement from publisher AIP Publishing. “Our study shows that high air speeds remain a significant hazard and can result in serious injury or even death.”
According to the study, simply being inside a stable building is not enough. Because narrow spaces can even increase the air speed. In addition, air is reflected by the pressure wave from walls and can even flow around corners in this way. According to the study, forces can arise that correspond to 18 times the body weight of a person.
“The most dangerous indoor spots to avoid are the windows, the corridors and the doors,” says author Ioannis Kokkinakis. “People should stay away from these places and seek shelter immediately.” But where? Best in the corners. The force of the air masses is lowest there. “Even in the front room exposed to the blast, you can be safe from the high air velocities by staying at the blast-facing corners of the wall,” Kokkinakis said.
However, the authors emphasize that the time between the explosion and the arrival of the blast wave is only a few seconds. It is therefore crucial to get to safety as quickly as possible. And the blast isn’t the only problem: there will also be “increased radiation levels, unsafe buildings, damaged power and gas lines, and fires,” Drikakis warns.
The authors hope their advice will never have to be followed. At the same time, they believe that understanding the effects of a nuclear explosion can help prevent injuries and guide rescue efforts.
