Was North Korean nuclear test a dud?

North Korea claims to have successfully tested a nuclear bomb and is awaiting congratulations. Even if the world had wanted North Korea to test, are kudos warranted?

Previously, North Korea caused a 2.3 magnitude seismic event using two metric tons of TNT. The event yesterday was magnitude 4.2, just about 100 times as powerful. Would that be equivalent to 2 metric tons X 100 = 0.2 kilotons TNT? If so, that’s not anywhere near the expected 20 kilotons of a nuclear test.

These are off-the-cuff questions by someone who has just enough knowledge to look stupid on the Internet. ArmsControlWonk has real equations, real knowledge, (a really funny picture), and comes to the conclusion that the test was a dud. Oops!

Update: Donald Sensing at One Hand Clapping says it’s too early to call the test a dud. North Korea may have designed a small yield nuke intentionally, in which case the test could be a success. Or North Korea may have used a ton (actually, quite a few tons) of conventional explosives in an attempt to fool the world.

Update 2: Russia claims the test’s yield was between 5 and 15 kilotons, not the 0.550 kilotons as measured by South Korea. Russia also claims North Korea warned them about the test two hours before it happened.

Update 3: U.S. intelligence agencies are questioning whether the explosion was nuclear.

We’re still evaluating the data, and as more data comes in, we hope to develop a clearer picture,” said one official familiar with intelligence reports.

“There was a seismic event that registered about 4 on the Richter scale, but it still isn’t clear if it was a nuclear test. You can get that kind of seismic reading from high explosives.”

“The underground explosion, which Pyongyang dubbed a historic nuclear test, is thought to have been the equivalent of several hundred tons of TNT, far short of the several thousand tons of TNT, or kilotons, that are signs of a nuclear blast, the official said.

The official said that so far, “it appears there was more fizz than pop.”