The independent resource on global security
From the evidence available, it is possible to conclude (with varying degrees of certainty) that the event was an underground nuclear test explosion of a plutonium device, that it took place in North Korea’s North Hamgyong province, and that the yield was approximately a few kilotons. Full verification of these conclusions would require on-site inspection.
Since 1945 there have been a total of 2054 nuclear explosions, including tests, explosions carried out for peaceful purposes and the two nuclear bombs dropped in August 1945.