Things that could cause the physical phenomena observed : If there was an explosion , the main possible causes : Finally , another way to divide up explosion hypotheses is by how intentional it was : North Korea 's claim to possess nuclear weapons on 10 February 2005 gives the nuclear testing or accident hypotheses some credibility . However , no neighboring nations have claimed any detection of radioactive isotopes which would be characteristic of either . North Korea claimed to have tested its first nuclear weapon on 9 October 2006 . There have since been multiple nuclear tests by North Korea
nuclear weapon on 9 October 2006
2006 North Korean nuclear test
Ryanggang explosion