AGU:

North Korea has been testing nuclear devices underground since 2006. The 2017 nuclear test caused a magnitude 6.3 earthquake, according to the US Geological Survey, and produced sound waves recorded by seismometers around the world. These reverberations are clues to the size of the blast, but determining the size of the explosion from a distance based on seismic recordings is not simple, said Lay, who has served on the Air Force Technical Application Center Seismic Review Panel tasked with advising on nuclear testing for over 25 years.

Unknown characteristics of the nuclear devices, the test sites and their geologic context create large uncertainties in estimates of explosion size. Previously published scientific estimates of the 2017 test’s size have ranged from 30 to 300 kilotons. The U.S. intelligence community has estimated the size of the explosion at 140 kilotons according to a report in The Diplomat magazine.

The new research puts the magnitude of the 2017 test in a range of 148 to 328 kilotons.

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