After North Korea conducted its sixth and largest nuclear experiment in September, signs have emerged that its test site in Punggye-ri may be falling apart.

A series of earthquakes, which is unusual in the area, have been recorded, while a massive tunnel collapse at the site was also detected. 


Japan’s Asahi TV on Tuesday reported that at least 200 people died and about 100 people were trapped inside in a collapsed tunnel, without providing information on when it had happened.

Seoul’s Unification Ministry said Wednesday that it has yet to confirm the report.

During a parliamentary audit in Seoul on Monday, Korea Meteorological Administration chief Nam Jae-cheol said that another detonation could possibly prompt a “collapse of the test site” and spill radioactive materials.

“Based on our analysis of satellite imagery, we judge that there is a hollow space, which measures about 60 to 100 meters (in length), at the bottom of Mantapsan in the Punggye-ri site,” Nam told lawmakers. “So, should another nuke test occur, there is the possibility (of a collapse).”

Days after the nuclear explosion in September, commercial satellite images showed apparent signs of multiple landslides around the site, which experts described as “more numerous and widespread” compared to previous experiments.

Concerned about nuclear waste contamination, Chinese scientists reportedly warned Pyongyang to relocate the test site, as Mantapsan, about 80 kilometers from the North Korea-China border, was at risk of collapse, Hong Kong’s South China Morning Post said. If the site deteriorates, a nuclear waste spill could seep through the border and spoil Chinese soil, they reportedly feared.

North Korea’s latest nuclear test on Sept. 3, which is also believed to be its strongest yet, may have dealt a heavy blow to its topography. The South Korean Meteorological Administration said the test caused an artificial magnitude 5.7 earthquake, while the US Geological Survey and Chinese government measured it at 6.3. Smaller tremors followed, which many saw as aftershocks of the detonation.

But a US think tank said that “for the time being,” Pyongyang has no plans to abandon the Punggye-ri test site, “given the presence of additional test portals.” Although substantial damage to the tunnels is suspected, similar nuclear tests conducted at the US Nevada Test Site and former Soviet nuclear test sites did not lead to site abandonment, according to analysis from 38 North of the US-Korea Institute at Johns Hopkins School of Advanced International Studies.

“North Korea currently has two options regarding military provocations -- conducting an intercontinental ballistic missile test or a nuclear test,” Koh Yoo-hwan, a professor of North Korean studies at Dongguk University said.

“However, if its nuclear test site (of Punggye-ri) is exhausted, there won’t be another nuclear experiment anytime soon,” he said.

On the possibility of an atmospheric nuclear test, Koh said that such decision entails a massive risk at the moment with US President Donald Trump’s scheduled visit to South Korea next week. At the UN General Assembly in New York last month, North Korean Foreign Minister Ri Yong-ho told reporters that Pyongyang is considering dropping a hydrogen bomb in the Pacific Ocean.

“The North will think twice before launching any sort of military provocation around the time of President Trump’s Asia tour. The regime will weigh the current situation and keep close tabs on how the situation shifts after the tour,” Koh added. The Seoul-based expert also ruled out the option of a submarine-launched ballistic missile, citing the North’s current lack of infrastructure.

By Jung Min-kyung (mkjung@heraldcorp.com)