Collapse of test site left North Korea with little choice but to suspend nuclear testing

Guardian:

North Korea’s main nuclear test site has partially collapsed under the stress of multiple explosions, possibly rendering it unsafe for further testing and leaving it vulnerable to radiation leaks, a study by Chinese geologists has shown.

The findings could cast doubt on North Korea’s sincerity in announcing last weekend that it would stop testing nuclear weapons at the site ahead of Friday’s summit between the country’s leader, Kim Jong-un, and the South Korean president, Moon Jae-in.

The test site at Punggye-ri, in a mountainous area in North Korea’s north-east, has been the location for all six of the regime’s nuclear tests since 2006.

The findings, by scientists at the University of Science and Technology of China, suggest the partial collapse of the mountain that contains the testing tunnels, as well as the risk of radiation leaks, have potentially rendered the site unusable.

The study was published soon after Kim said his country would stop testing nuclear weapons and ballistic missiles, and close down Punggye-ri before his meeting with Moon just south of the countries’ heavily armed border.

Nuclear explosions release enormous amounts of heat and energy, and the North’s largest test, in September last year, was believed early on to have rendered the site - a network of tunnels beneath Mount Mantap - unstable.

The Chinese scientists collected collected data for their study following the most powerful of the North’s six nuclear tests, on 3 September.

The controlled explosion, which caused an initial magnitude-6.3 tremor, is believed to have triggered four more earthquakes over the following weeks. The study concluded that eight-and-a-half minutes after the test, there was “a near-vertical on-site collapse towards the nuclear test centre”.

The Chinese university paper, written by Tian Dongdong, Yao Jiawen and Wen Lianxing, said that was followed by an “earthquake swarm” in similar locations.
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With the collapse of their test site and the crushing of the North Korean economy by sanctions, Noth Korea decided to take a chance on peace.  Whether it will follow through is still an open question and whether it will live up to the commitments needed to lift the sanctions is still an open question.  In the past, their word has been no good.