The Mainichi answers some questions readers may have about North Korea's nuclear program and its use as a possible negotiation tool.
Question: Did North Korea conduct another nuclear test?
Answer: Yes, the North Korean government announced on Sept. 3 that it successfully tested a hydrogen bomb that can be mounted on its intercontinental ballistic missiles. The Japan Meteorological Agency estimates that the blast was roughly 10 times that of North Korea's previous nuclear test in September 2016 -- the largest yet.
While atomic bombs (A-bombs) use the energy produced by the fission of uranium or plutonium for a blast, hydrogen bombs (H-bombs) use hydrogen isotopes such as deuterium and tritium to create a nuclear fusion reaction with an energy output much greater than an atomic bomb. The H-bomb test the United States conducted on the Bikini Atoll in the Pacific Ocean in March 1954 was approximately 1,000 times the strength of the A-bomb detonated in Hiroshima.
Q: That's scary, isn't it?
A: The blast power isn't the only scary thing. The newly developed warheads are also reportedly capable of attack by electromagnetic pulse. By generating electromagnetic waves from the bomb blast, North Korea could mount an additional attack by disrupting the functions of information communications devices. A large-scale blackout could occur in the target city, paralyzing infrastructure and possibly causing a great deal of damage.
Q: Why is North Korea developing an H-bomb?
A: There is speculation that North Korea is developing powerful nuclear weapons in order to be recognized as a nuclear power by the United States and other nations. The Kim Jong Un regime is believed to also be creating leverage for future negotiations in hopes of guaranteeing the safety of the country. However, at the moment, it is unlikely that the United States and other countries will allow North Korea to possess such weapons, and will likely strengthen sanctions. (Answers by Aya Takeuchi, Foreign News Department)