According to a February 26 Global Security Newswire story, the recent North Korean nuclear test "brought fresh attention to the capabilities" of the CTBTO's monitoring system. The CTBTO's International Monitoring System (IMS) was able to detect the North Korean nuclear test within moments and forwarded information from its seismic and infrasound stations to state parties just over an hour after the explosion.

The IMS was also able to record the February 15 meteor explosion over the Ural Mountains in Siberia with 17 of its 45 infrasound stations. The IMS currently employs 274 certified stations around the globe, using a combination of seismic, infrasound, hydroacoustic, and radionuclide sensors to record nuclear test explosions.

The government of the Democratic People’s Republic of Korea (DPRK) has apparently conducted its third nuclear test explosion, defying the explicit demands of the UN Security Council and the international community that it “abandon all nuclear weapons and existing nuclear programmes in a complete, verifiable and irreversible manner.”

The Executive Secretary of the Comprehensive Test Ban Treaty Organization (CTBTO), Tibor Toth, issued the following statement on Feb. 12 at  04:19:17 CST:

“Today our monitoring stations picked up evidence of an unusual seismic event in the Democratic People’s Republic of Korea (DPRK). The event shows clear explosion-like characteristics and its location is roughly congruent with the 2006 and 2009 DPRK nuclear tests. For now, further data and analysis are necessary to establish what kind of event this is. If confirmed as a nuclear test, this act would constitute a clear threat to international peace and security, and challenges efforts made to strengthen global nuclear disarmament and non-proliferation, in particular by ending nuclear testing.”

The Comprehensive Test Ban Treaty Organization (CTBTO) announced this week that the organization is able to detect seismological activity in North Korea "within minutes" of an explosion. Following North Korea's previous nuclear tests in 2006 and 2009, the CTBTO was able to determine "within a couple of hours" of each event that they were explosions, not earthquakes. 

Sandia National Laboratories recently tested an unmanned aerial vehicle (UAV), nicknamed "Harvester," for use in detecting nuclear test explosions. The UAV's airborne pods are equipped with radiation sensors and debris samplers, which can track radiation to its source and use particulates and gases to identify the location of a nuclear test explosion, according to a press release from Sandia.

Harvester differs from traditional nuclear test monitoring technology in that it actively investigates sources of radiation, as opposed to the immobile monitoring stations used by the United States and CTBTO, while avoiding the health risks involved with sending a manned aircraft to investigate a radioactive plume.

Today, North Korea’s National Defence Commission released a statement ramping up the rhetoric towards the United States. Pyongyang announced its intention to conduct a nuclear explosion of a higher yield than its previous tests in 2006 and 2009. The country also announced that it plans to continue to launch satellites and long-range rockets in direct violation of several UN Security Council resolutions.

Pyongyang stated that its “upcoming all-out action” would target the United States and that “settling accounts with the U.S. needs to be one with force, not with words.”

In 2011, the U.S. Senate voted unanimously to designate January 27 as a "national day of remembrance for Americans who, during the Cold War, worked and lived downwind from nuclear testing sites and were adversely affected by the radiation exposure generated by the above ground nuclear weapons testing."

In a major speech on Jan. 18, UN Secretary-General Ban Ki-moon spoke on a range of nuclear disarmament and nonproliferation issues at the James Martin Center for Nonproliferation Studies in Monterey, California. He touched on the international community's achievements on nuclear disarmament and nonproliferation, outlined the the challenges that lay ahead, and called for renewed action on key priorities including the CTBT:

The Advisory Committee of the Confidentiality of National Defense has approved the declassification of 58 documents related to radiation levels in French Polynesia during and after French nuclear test explosions. 

France conducted 4 atmospheric and 13 underground nuclear tests in Algeria and 46 atmospheric and 147 underground nuclear tests at the Mururoa and Fangataufa Atolls in the Pacific.