With most media focusing on the geopolitical and military consequences of Pyongyang’s September nuclear test, another important consideration has largely gone undiscussed: the human cost. Nuclear testing is dangerous. Not only can it cause immediate damage to the surrounding environment, it can also cause lasting damage to much larger areas around the test site. Just ask Fukushima.

Since all of North Korea’s nuclear tests have been conducted underground and inside of a mountain (Mantapsan), the common assumption is that environmental damage has been minimal. Unfortunately, this isn’t necessarily true. Pyongyang’s latest test essentially released the same amount of energy as a magnitude 6.3 earthquake. This is about the same strength as the earthquake that shook China’s Sichuan province last August, causing landslides that killed 25 people in a very rural area.

Since North Korea’s Punggye-ri nuclear site is also located rurally and far from any large human habitation, the 6.3 quake likely didn’t cause much immediate human damage. Dwellings in a 20-kilometer radius likely only had walls crack, windows break, and underground pipes snap. What is more concerning is the fact that the initial 6.3 tremor was followed eight minutes later by a second tremor of magnitude 4.6.

For natural earthquakes, secondary tremors are very normal. In natural earthquakes, the earth shakes because it is rearranging itself to relieve pressure built up over time. Such rearrangements can never take place in a single moment so natural earthquakes usually consist of one or two major tremors and tens or hundreds of minor ones taking place over the span of hours, days, or even weeks. Major tremors relieve large amounts of pressure while smaller ones relieve less.

Nuclear tests are not supposed to have secondary tremors because they are not caused by pressurized earth that needs relief. This is why the second tremor of 4.6 is so worrisome: It suggests that some part of the mountain housing the test facility may have collapsed. This idea is supported by recent photos published by the BBC showing multiple landslides and redistribution of gravel around Mantapsan.

If true, even a partial collapse of the test facility could have dire consequences for the containment of radioactive waste. Even a small leak could cause sever contamination of the watershed running down from Mantapsan, feeding rivers that empty into the East Sea near the towns of Kimchaek and Orang. Kimchaek is North Korea’s 16th largest city, with about 200,000 inhabitants. From Mantapsan to Kimchaek, the watershed covers a distance of about 30 kilometers, similar to the radius of contamination caused by the Fukushima incident.

China was quick to say its border with North Korea was unaffected by September’s nuclear test, announcing the result within two days. The announcement was, however, not surprising because the Mantapsan watershed goes in the opposite direction: away from the Chinese border and toward the East Sea. Even if the leak started right now, the Chinese would likely not know for weeks.

It is, of course, by design that the Punggye-ri facility was placed far from China and areas with denser habitation. Nevertheless, the possibility of radioactive leakage is still a real threat that needs to be considered. If, for example, North Korea announced that thousands of people in Kimchaek had been contaminated, how should the international community respond? How should South Korea respond?

North Korea clearly lacks the technology, experience and personnel to deal with a radioactive incident of that size. Should the international community respond with nothing and let thousands of people get sick and die? Or do other countries have a moral obligation to step in and help? If so, what should that help consist of? These are not easy questions.

The only thing that is certain is that a contamination incident would most likely force South Korea to take the lead and foot most of the bill, either as part of a relief operation immediately or as part of a reunification effort later. Either way, Kim Jong-un’s efforts to solidify power through nuclear weapons seem more and more likely to stamp a permanent and unfortunate radioactive legacy on the land.


By Justin Fendos

Justin Fendos is a professor at Donseo University in Korea and the associate director of the Tan School at Fudan University in Shanghai. -- Ed.