A 38 North exclusive with analysis by Joseph S. Bermudez Jr. and Jack Liu.

Over the past four weeks, there have been unusually high levels of activity at the Punggye-ri Nuclear Test Site, especially around the North Portal—the tunnel in which the four most recent nuclear tests have taken place. New commercial satellite imagery from April 2 indicates continued activity in this area and at the Main Administrative Area, while the rest of the facility remains quiet. This pattern of activity could mean a sixth nuclear test is imminent, but the imagery does not provide any definitive evidence of the installation of a nuclear device or the exact timing of such a test.

At the North Portal, water continues to be pumped out of the tunnel and is saturating the ground to the southeast. The melting snow and resulting visible paths indicate continued foot and vehicle traffic around the portal and what appear to be two small trailers are visible on the side of the road to the south. The probable netting that was installed previously near the support building appears to be suspended over equipment—precisely what equipment can’t be determined at present. Additionally, there may have been some new dumping of material excavated from the tunnel onto the spoil pile.

Figure 1. Activity continues at the North Portal.

Figure 2. Possible new dumping observed at the North Portal spoil pile.

In the northern courtyard of the Main Administrative Area there appears to be either a formation of personnel or rows of equipment or supplies, but the resolution of the imagery is insufficient to make a determination. No recent vehicle tracks are noted in any of the courtyards.

Figure 3. Probable personnel in formation or equipment in rows at the Main Administrative Area.

No activity of significance is noted at the West or South Portals, Command Center Area, or the main guard barracks and security checkpoint.