Kim Jong-un seems to share his dad's love of things that go boom:

American and South Korean officials reported seismic activity in North Korea on Tuesday that appeared to be evidence of the country’s third, and long-threatened nuclear test and a new challenge for the Obama administration in its effort to keep the country from becoming a full-fledged nuclear power.

The blast was reportedly in the range of six or seven kilotons. For comparison's sake, the bomb we dropped on Hiroshima was approximately 12.5 kilotons. There has been no comment from the White House yet.