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. (Read more North Korea stories.)