North Korea's relentless march to nuclear prowess

North Korea said its latest test was of a hydrogen bomb that can be mounted on a long-range missile

North Korea’s six nuclear tests since 2006 have been part of a program to develop nuclear-tipped missiles that can threaten the U.S. and its allies. Each test has shown progress toward that goal.

Oct. 9, 2006

Magnitude of earthquake: 4.1

Estimated yield of explosion: Less than 1 kiloton

After sporadic multilateral talks with North Korea for years over its nuclear ambitions, the nation exploded a device that was widely viewed as partially successful test of a nuclear bomb.

May 25, 2009

Magnitude of earthquake: 4.7

Estimated yield of explosion: 2-6 kilotons

North Korea’s second nuclear test was viewed by experts as successful. It came soon after Pyongyang fired a long-range rocket that landed in the Pacific Ocean and was viewed to be a missile test.

Feb. 12, 2013

Magnitude of earthquake: 5.1

Estimated yield of explosion: 7 kilotons

North Korea said after its third test that it had detonated a “miniaturized and lighter” device, suggesting it was making progress toward having a bomb small enough to mount on a long-range missile.

Jan. 6, 2016

Magnitude of earthquake: 5.1

Estimated yield of explosion: 7 kilotons

North Korea said its next nuclear detonation was the first test of a hydrogen bomb, a more powerful device that a standard atomic weapon. Experts said the explosion was too small to have been a hydrogen-based device, but may have been boosted with hydrogen.

Sept. 9, 2016

Magnitude of earthquake: 5.3

Estimated yield of explosion: 10 kilotons

North Korea’s fifth nuclear test also didn’t appear to be big enough for a standard hydrogen bomb, but it said after the explosion it was now able to produce nuclear warheads for missiles “at will.”

Sept. 3, 2017

Magnitude of earthquake: 6.3

Estimated yield of explosion: About 100 kilotons

North Korea said its latest nuclear test was of a hydrogen bomb that can be mounted on a long-range missile. Experts are now evaluating those claims. Earlier in the day North Korea published photos of leader Kim Jong Un inspected what it called a hydrogen bomb.

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Sources: U.S. Geological Survey; South Korean government.

Source: The Wall Street Journal