On May 25, North Korea detonated another nuclear device. The MSM claimed that the blast equaled the Hiroshima or Nagasaki bomb. Many worried that nuclear war with Korea was imminent. Russia put its troops in the Far East on alert.

Relax. The latest North Korean nuke was a dud, just like the one they exploded on October 9, 2006.

A nuclear bomb tested underground resembles an earthquake in many ways, and the yield of the nuclear explosion can be determined by the magnitude of the quake on the Richter scale. The MSM reports were based on Russian seismic stations, and these usually report higher magnitude than other observers. I always wait for the report of the Comprehensive Nuclear Test-Ban Treaty Organization, which includes not only the Russian data, but also the observations of earthquake observatories throughout the world — 61 seismic stations recorded the latest North Korean blast. Since the CTBTO combines all the world’s observations, it is the most reliable source of nuclear blast magnitudes.

They report that the latest North Korean nuclear bomb measured 4.53 on the Richer scale, whereas the 2006 bomb was 4.1. This means that the latest explosion was indeed more powerful than the 2006 blast, but not enormously so.

Converting measured earthquake magnitude to explosive yield depends on knowledge of the geology of the test site, which, not surprisingly, the North Koreans have not provided. But we can make some educated estimates. In my judgment, the May 25 bomb was about 3.5 times as powerful as the 2006 device. The general expert opinion, which I share, was that the 2006 bomb had a yield between 0.1 and 0.8 kilotons, so the most recent explosion was between 0.4 and 2.8 kilotons. (My own guess is on the lower end of this range.) Yale geologist Jeffrey Park has reached a similar conclusion.

In other words, both bombs were much less powerful than the Hiroshima bomb, an enriched uranium bomb that had a yield of 15 kilotons, and also less powerful than the Nagasaki bomb, a plutonium bomb that had a yield of 21 kilotons. In the terminology of nuclear weapons designers, both North Korean nuclear tests were “fizzles.”

The fact that both tests were fizzles has three important implications. First, both tests were tests of a plutonium bomb. Second, it is highly unlikely that the Iranians had anything to do with either test. Third, it is highly unlikely that the North Koreans have developed the technology for enriching uranium to weapons grade.