Explosive actions Blasts gain in strength

1 Oct 9 2006.

Yield: 0.7 kilotons Underground blast follows a warning from Pyongyang.

2 May 25 2009.

Yield: 5.4 kt. Three shortrange missiles are test-fired from an east coast military base after the underground atomic explosion, as powerful as the Hiroshima bomb.

3 Feb 12 2013.

Yield: 12.2-16kt. Pyongyang tests a “miniaturised” nuclear device.

4 Jan 6 2016.

Yield: 7.1-15.5kt. First underground test of a hydrogen bomb, although some experts believe it more likely involved a uranium or plutonium device.

5

Sept 9 2016:

Yield: 15-25kt. The regime announces the successful test of a warhead that can be mounted on a strategic range ballistic missile.

6 Sept 3 2017.

Yield: over 100kt (estimate). Pyongyang’s largest hydrogen bomb yet causes an earthquake felt as far away as Vladivostok. The “perfect” test was carried out to check “power control technology” and a new design for producing an “H-bomb to be placed as the payload of the intercontinental ballistic missile”, says state TV.