North Korea's Nuke Test May Have Been Twice as Strong as Thought

How U.S.-North Korea Tension Could Lead to War

North Korea’s latest nuclear test may have been more than twice as powerful as first thought -- or 17 times stronger than the Hiroshima bomb -- according to an analysis by 38 North.

New seismic data from the Sept. 3 explosion suggest a blast of about 250 kilotons, compared with an initial estimate of 120 kilotons, analysts Frank Pabian, Joseph Bermudez Jr. and Jack Liu wrote for the website, which is run by the U.S.-Korea Institute at Johns Hopkins University’s School of Advanced International Studies. The energy released by the U.S. bomb detonated over Hiroshima in 1945 was about 15 kilotons.

QuickTake North Korea's Nukes

The test -- North Korea’s sixth -- was part of a weapons program under leader Kim Jong Un, who has vowed to develop missile technology that can deliver a nuclear warhead as far as the U.S. mainland. In response, the United Nations Security Council approved new sanctions against North Korea on Monday to pressure Kim into negotiations about giving up his weapons.

The 38 North analysis said a 250-kiloton yield was close to what it had previously determined was the maximum that could be contained by North Korea’s underground Punggye-ri test site. Satellite imagery appears to show landslides atop the site that were more numerous and widespread than after the previous five tests.

There also appears to be increased water drainage around the site’s north portal area, possibility as a result of the test, 38 North said. Such underground water flow could carry contamination to the surface and wasn’t inconsistent with a South Korean report finding radioactive material in the environment, the authors said.

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— With assistance by Andy Sharp

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