RUSSIA CHINA Shenyang Punggye-ri nuclear test site NORTH KOREA Pyongyang Sea of Japan (East Sea) Seoul SOUTH KOREA Busan 100 miles JAPAN 100 km 
 
 The research feeds into an international debate over the value of Mr. Kim’s commitment to close the test site in the run-up to last month’s inter-Korean summit and his meeting with President Donald Trump, expected this month or early next. Some U.S. officials and experts see the closure as a significant concession while others argue that the site is unusable and its dismantling is therefore an empty gesture designed to gain leverage in negotiations with Seoul and Washington. Mr. Kim told South Korean President Moon Jae-in at their summit that two bigger tunnels at the site were still in good condition, according to Seoul’s presidential Blue House.
– The nuclear test site that Kim Jong Un promises to shutter may be in worse shape than the world knew, the Wall Street Journal reports. The Punggye-ri site—which is couched in a mountain called Mount Mantap—apparently suffered a sizeable collapse in the hours and days after North Korea's most recent nuclear test in September. An international team of scientists reached this conclusion by combining seismic data with satellite radar images, Nature reports. "These findings make us infer that a large part of the Punggye-ri test site is inoperable," says a USC professor. Seismologists have already shown that a big part of the site was unusable after the last test caused a near-immediate collapse of a cavity in Mount Mantap. The latest study used synthetic aperture radar—which is normally used to make 3D terrain maps—to show that Mantap's slopes moved outward horizontally by nearly four yards, and the summit sank by about half a yard over the next week when "damaged rock above the cavity slowly settled in on itself," says Nature. The latest finding may add to concerns that Kim's plan to close Punggye-ri before meeting President Trump isn't much of a concession. North Korea said Saturday that it plans to dismantle Punggye-ri on May 23-25, the AP reports.