North Korean A-Bomb May Have Been A Dud

Based on seismic data for Russia and other sites around the globe, it appears that the North Korean underground nuclear weapons test may have been almost an order of magnitude smaller than the ones used at Hiroshima and Nagasaki. The test back in October 2006 had an even smaller yield.

The technology is very challenging and the North Korean effort may have hit several limitations. Not to say they will not eventually get there.