North Korea Conducts Nuclear Test

Patricia Lewis
May 25, 2009

On May 25, 2009, the (North) Korean Central News Agency (KCNA) announced that North Korea had carried out a nuclear test that was safely conducted on a new higher level in terms of its explosive power and technology of its control.

The test will, according to KCNA, “contribute to safeguarding our sovereignty and socialism and guaranteeing peace and safety on the Korean peninsula and the surrounding region.”

North Korea Conducts Nuclear Test: North Korean rocket launch

North Korean rocket launch, Source: KCNA

Rocket Launch Details

The US Geological Survey (USGS) estimates:

  • a magnitude of 4.7 on the Richter Scale
  • at coordinates of 41.331°N, 129.011°E
  • 75 km (45 miles) NNW of Kimchaek, North Korea
  • 95 km (60 miles) SW of Chongjin, North Korea
  • 180 km (110 miles) SSW of Yanji, Jilin, China
  • 380 km (235 miles) NE of Pyongyang, North Korea

USGS’s summary stated that while it cannot confirm that the recent event was a nuclear test, it was shallow and located in the vicinity of the October 2006 North Korean nuclear test, which had a magnitude of 4.3.

International Monitoring

Seismic Activity

The provisional secretariat of the international organization charged with monitoring nuclear testing activities – the Comprehensive Test Ban Organization (CTBTO) – proved its international monitoring system’s capabilities with the first North Korean nuclear test on October 9, 2006. Today, the CTBTO announced that its international monitoring system test again demonstrated its ability to monitor the nuclear test ban successfully. Twenty-three primary seismic stations (compared with thirteen in 2006) picked up the signals. The closest IMS station to the event was at Ussuriysk, Russia, and the furthest in Texas, USA. It is worth noting that since the last nuclear test, the number of seismic stations in the CTBTO IMS network has increased from 89 to 130.

Noble Gases

The next step by the CTBTO monitoring system will be to detect radioactive particulates or noble gases, such as Xenon 133, released into the atmosphere by underground nuclear tests. In 2006, there were 10 noble gas network systems; today there are 22. Some of the new stations are situated close to North Korea, in China, Japan and Russia. While the exact meteorological situation will determine how long it will take for these stations to detect radioactive noble gases, the period of time is likely to be shorter than in 2006, when it took two weeks for the gases to be detected at Yellowknife, Canada. (See complete CTBTO press release on the North Korea test.)

Explosive Yield

The event corresponds to an explosive yield of about 3 to 8 kilotons TNT equivalent with a most likely yield of 4 kt TNT, according to the assessment of Martin Kalinowski of the Carl Friedrich von Weizsäcker Center for Science and Peace Research at the University of Hamburg. In 2006 the yield was unexpectedly low with an estimate of 0.5 to 0.8 kt TNT. However, according to press reports, the Russian Defense Ministry estimated the explosion to be equivalent to 10-20 kilotons. It should be noted that the Russian Federation initially overestimated the October 2006 test.

International Statements

United States

In an initial reaction to the launch, U.S. President Barack Obama stated:

By acting in blatant defiance of the United Nations Security Council, North Korea is directly and recklessly challenging the international community. North Korea’s behavior increases tensions and undermines stability in Northeast Asia. Such provocations will only serve to deepen North Korea’s isolation. It will not find international acceptance unless it abandons its pursuit of weapons of mass destruction and their means of delivery.

The danger posed by North Korea’s threatening activities warrants action by the international community. We have been and will continue working with our allies and partners in the Six-Party Talks as well as other members of the U.N. Security Council in the days ahead.

President Obama said that North Korea conducted the nuclear test in violation of international law, that North Korea’s actions are a matter of grave concern to all nations and that North Korea’s attempts to develop nuclear weapons, as well as its ballistic missile program, constitute a threat to international peace and security. In a later statement, President Obama noted that North Korea will not find security and respect through threats and illegal weapons. He added that the United States and the international community must take action in response.

Comprehensive Test Ban Organization

Tibor Tóth, Executive Secretary of the Preparatory Commission for the CTBTO, said:

Today’s claim by the Democratic People’s Republic of Korea (DPRK) that it has conducted a nuclear test constitutes a threat to international peace and security and to the nuclear nonproliferation and disarmament regime. I am gravely concerned by this action. In particular, it is a serious violation of the norm established by the Comprehensive Nuclear-Test-Ban Treaty (CTBT) and as such deserves universal condemnation.

Today’s event underlines the urgency of the entry into force of the CTBT and the necessity of putting an end to all nuclear explosions for all time. It is therefore my hope that the current situation will increase political momentum towards the CTBT’s entry into force and speed up the ratification process.


The Chinese Foreign Ministry issued a strong statement saying:

The DPRK ignored universal opposition of the international community and once more conducted the nuclear test. The Chinese government is resolutely opposed to it. Beijing also called on North Korea to fulfill its nuclear disarmament pledges, refrain from actions that could further escalate the situation, and return to the Six-Party Talks. The statement also calls on all the relevant parties to address the issue with calm and through diplomacy and dialogue.


The Russian Foreign Ministry has said that the test evokes concern. Moscow called on our North Korean partners to display a responsible attitude for the sake of regional stability, the nonproliferation of weapons of mass destruction and the respect for and observation of the UN Security Council resolutions. The Russian Foreign Ministry statement further noted that: “We still think that the nuclear problem of the Korean Peninsula may be resolved only at the six-nation negotiations.”

United Nations Security Council

The UN Security Council unanimously condemned the nuclear test of 2006 in its Resolution 1718 (14 October 2006) and demanded that North Korea not conduct any further nuclear test or launch of a ballistic missile. In response to the May 25 test, Japan has requested a UN Security Council meeting. Kazuo Kodama, a spokesman for Japan’s Ministry of Foreign Affairs said: “We are now aware of the news that North Korea conducted a nuclear test for the second time, so we are certainly going to respond in a very responsible manner. Definitely we are going to respond, we have to, at the UN Security Council.”

The Russian Federation, currently chairing the UN Security Council, will hold an emergency meeting of the council today to discuss the response to the test.

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