Immediately following the test earlier this month, White House Press Secretary Josh Earnest said the initial analysis that have been conducted was “not consistent” with a successful hydrogen bomb test.
The U.S. still does not accept North Korea’s claim that it tested a hydrogen bomb, but air sampling conducted after the test has proved inconclusive, the official said. That prompted another look at the seismic data.
However, the size of the seismic event and other intelligence indicates it was not likely a fully functioning device. The official said it’s possible the North Koreans believe they conducted a full hydrogen bomb test, but the U.S. believes it was likely only some components, perhaps a detonator, that exploded.That analysis shows the test was conducted more than two times deeper underground than originally assessed — at a depth consistent with what might be needed for a hydrogen bomb.