h bomb test

Radiation levels increased near the place where the North tried the H bomb
Monitoring stations on the China-Korea border detect a trend of increased radiation, but experts suspect this may be due to natural causes instead of the H. bomb test.
Suspected that the crust shifted after the Korean nuclear test
According to Reuters, the test in early September 2017 may be the cause of two vibrations discovered on December 9, 2017, testing the Korean Punggye-ri nuclear.