The first announced DPRK nuclear test:
Baptism of fire for the CTBT verification regime

9 October 2006 - First DPRK nuclear test

On 9 October 2006, the Democratic People’s Republic of Korea (DPRK) conducted its first nuclear test, thus breaking the de-facto moratorium put in place by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The test was met with universal condemnation; the United Nations Security Council described it as a “clear threat to international peace and security” and unanimously adopted sanctions through resolution 1718. The Chairman and the Executive Secretary of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) as well as CTBTO Member States expressed grave concern.

Seismograms for the 2006 nuclear nuclear test(top) and for an earlier earthquake in the same region.

While the DPRK had announced its intention to conduct a nuclear test some days before, it had not provided any details. When the test occurred, it was well-recorded throughout the world by the CTBTO’s International Monitoring System (IMS), despite its small yield and the fact that the IMS was only 60% operational at the time. Over 20 IMS seismic stations, including one as far away as South America, registered the shock waves which clearly showed explosion-like characteristics.

The signal’s origin was narrowed down to an area significantly less than 1,000 square kilometres.



Data from the recordings were available at the International Data Centre in Vienna in near real-time. Less than two hours after the explosion, CTBTO Member States received the first automatic analysis of the time, location and magnitude. More detailed analyses followed later. The signal’s origin was eventually narrowed down to an area significantly less than 1,000 square kilometres – the size of the area that may be investigated during an on-site inspection (OSI).


Two weeks after the DPRK ‘s nuclear test, the IMS radionuclide station at Yellowknife, Canada, registered an increase of the level of the radioactive noble gas xenon. The prevailing meteorological conditions showed that these findings could be attributed to the explosion, thus providing the radioactive “smoking gun” evidence that the explosion was indeed nuclear.

This station at Yellowknife, Canada, found the “smoking gun” evidence.


The second DPRK nuclear test in 2009 also sparked worldwide outrage and was unanimously condemned by the UN Security Council. The international community has therefore shown zero tolerance for all nuclear tests conducted since the adoption of the CTBT in 1996 (including the Indian and Pakistani tests in 1998).


Nonetheless, nuclear tests will only be completely outlawed once the CTBT enters into force. Eight ratifications are missing: China, Egypt, India, Israel, Iran, the DPRK, Pakistan and the United States. Until the CTBT takes full legal effect, the absence of nuclear tests continues to rely on moratoria which are voluntary, unilateral declarations.