By now, a familiar pattern has emerged.
Pyongyang tests a bomb or a rocket and makes a grand declaration about its success. Quickly, others deny that they've accomplished quite what they say, questioning the yield of the explosion or the success of the launch — this time, Pyongyang stated they detonated a hydrogen bomb — foreign experts question that claim. The media publishes photos of South Koreans watching TV news, looking anxious (they aren't.) Members of the United Nations Security Council get together and a couple of weeks later pass a resolution condemning the test and adding sanctions.
What might the effects of Pyongyang's fourth nuclear test be?