North Korea nuclear test: How to hide a nuclear explosion

Could North Korea Have Tested Its Nuclear Weapon Undetected?

Answers to your questions about the news.
Feb. 12 2013 8:37 PM

The Boom Heard 'Round the World

Could North Korea have done more to hide its nuclear test?


Photo by Michel Baret/Gamma-Rapho/Getty Images

North Korea claimed to have carried out its third nuclear test on Tuesday, after a 4.9-magnitude earthquake was detected near the country’s known underground nuclear test site. North Korea, which the U.N. has banned from conducting such tests, apparently didn’t try too hard to keep the test a secret. Is there any way to hide a nuclear explosion?

Forrest Wickman Forrest Wickman



Decoupling has been accomplished on a few rare occasions before. In 1966 the U.S. detonated a 0.38-kiloton explosion. In 1976, the Soviet Union partially decoupled an 8-to-10-kiloton explosion in a 243-foot-diameter salt dome buried almost 3,000 feet below Kazakhstan. However, the explosion was recorded by seismic instruments as far away as Canada. Both cavities had been hollowed out by previous nuclear explosions several times larger, at 5.3 kilotons and 64 kilotons, respectively.


Another theoretical concern is that someone could hide a nuclear explosion by concealing it within an even bigger explosion, such as a large chemical explosion in a mine, in a hypothetical scenario known as “mine masking.” However, such a technique is difficult in practice for several reasons. Perhaps the most significant is that such large explosions, especially ones that are instantaneous in a manner similar to nuclear bombs, are extremely rare, and so just about any explosion of this size would attract some suspicion. This would, once again, mean that the device would have to be relatively small. Along the same lines, the proposed method of “hiding signals of an explosion in that of an earthquake” is impractical, both because of the difficulty of synchronizing the explosion with the time and location of an earthquake, and because the explosion’s seismic signature could still be filtered out.

Detonating a large nuclear device either underwater or high up in the sky would be even more difficult to hide. To detect explosions underwater, the CTBTO has 11 hydroacoustic stations in eight countries, which listen for sound waves travelling through the oceans. To detect explosions in the air, it has 80 radionuclide stations in 27 countries, each of which can detect radioactive particles blown by the wind from nuclear test sites miles away. Even explosions deep underground can release radioactive noble gases to the surface, which can be detected by 40 of the radionuclide stations. And these aren’t the only ways explosions can be detected from far away. Most explosions could be seen on satellites and could cause any nearby gamma ray and radio telescopes to light up with the sudden activity. They also cause a large electromagnetic pulse, which can cause radio interference, power surges, and can even fry some electronic devices. The CTBTO also has 60 stations sensitive to low-frequency sound waves (infrasound) given off by large explosions. Underground tests can even be visible to the naked eye, as they can cause the ground to settle in above them, leaving a large implosion crater.

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