There's a debate about the value of North Korean leader Kim Jong Un's promise to shut down North Korea's largest nuclear test site as he engages in peace talks with South Korea and President Trump's administration, but a study published in the journal Science on Thursday suggests the Punggye-ri site was largely destroyed after Pyongyang's last nuclear test in September. In the new study, researchers from the U.S., China, Germany, and Singapore created a 3-D model of the site based on space-based radar, and they found that the test tunnels continued caving in for hours and days after the explosion, causing more extensive damage than previously believed.
The damage first discerned at the site, under Mt. Mantap, was "dwarfed" by the subsequent collapses, says Sylvain Barbot, an author of the study from Singapore's Nanyang Technological University and the University of Southern California. "These findings make us infer that a large part of the Punggye-ri test site is inoperable and that further test may require a substantial investment in the construction of another facility elsewhere." Kim told South Korean President Moon Jae-in at this historic summit that two of the site's larger tunnels are still in good condition, Seoul says. Kim is meeting with Trump in Singapore on June 12. Peter Weber