A 38 North exclusive with analysis by Frank V. Pabian, Joseph S. Bermudez Jr. and Jack Liu

Recent commercial satellite imagery indicates that despite the continuation of small tremors near Mt. Mantap since North Korea’s last nuclear test, tunnel work at the Punggye-ri Nuclear Test Site is still underway. These efforts continue to be concentrated at the West Portal, leaving the North Portal—where the last five tests were conducted—mostly dormant and likely abandoned, at least for the time being.

At the West Portal, there has been a consistently high level of activity since North Korea’s last nuclear test. This includes a routine presence of vehicles and personnel around the portal, movement of mining carts from the portal to the adjacent spoil pile and signs of fresh spoil being dumped onto the pile. These activities suggest that tunnel excavation is underway at the West Portal, as the North Koreans expand the site’s potential for future nuclear testing.

Figures 1-4. High level of activity consistently observed at the West Portal.