The surveillance pictures, dating to Dec. 13 and earlier, show a new "tent cover or awning" whose purpose might be focused on safeguarding sensitive machinery from severe weather. The North was earlier detected to have taken swift action to repair damage to its testing site sustained from summer flooding, 38 North noted. The website is operated by the U.S.-Korea Institute at Johns Hopkins University.
"Water first spotted streaming out of the suspected test tunnel in a Nov. 19 satellite photo and still present almost a month later, may present a problem for Pyongyang," the analysis states. "In order to maintain a high level of readiness, the North Koreans will have to prevent water buildup in the tunnel that could possibly damage the nuclear test device and associated sensors designed to gather data on a detonation."
38 North said it could not determine if this possible challenge had been suitably addressed by the North. A third nuclear test could come as soon as 14 days following an official order from the Kim Jong Un regime, the website said.
The North in December conducted the latest launch of a long-range space rocket. The nation's previous nuclear tests, in 2006 and 2009, have come shortly after such launches.