How Scientists Know the North Korea Blast Probably Wasn't an H-Bomb
Earnest: Analysis Not Consistent With North Korea Claims
National security experts were quick to express doubt about North Korea's claim that it tested its first hydrogen bomb on Wednesday. This chart explains why: The seismic effects of the explosion are too similar to previous explosions, in 2013, 2009, and 2006, which were all confirmed as underground nuclear tests. A true hydrogen bomb would have caused a larger seismic reading.
The chart shows seismic activity detected in the northeastern Chinese city of Mudanjiang early this morning compared to the previous explosions, according to scientists at Columbia University's Earth Institute. The monitor is still for nearly a minute into the reading, followed by two large pulses about eight seconds apart. The shockwaves gradually dissipate after several minutes.