November 18, 2019 13:25
An Indian team of scientists has estimated the explosive yield of the nuclear weapon detonated by North Korea on Sept. 3, 2017 at 245 to 271 kilotons of TNT.
The estimate was made by a team led by K. M. Sreejith of the Indian Space Research Organisation based on satellite observations.
The new estimate is more than double the 120 kilotons that were estimated by an international research team of U.S. and German scientists and published in Science Magazine last year.
If correct, the yield was 17 times as high as the 15-kiloton Hiroshima bomb of 1945. The outcome of the latest research was published in Geophysical Journal International.
The research team analyzed radar images taken by ALOS-2, a Japanese satellite, of the area in and around Mt. Mantap in North Hamgyong Province where the North conducted its sixth nuclear test.
According to the team, the base of the mountain moved a few meters immediately after the nuclear explosion and the flank of the mountaintop also moved 0.5 m. The blast occurred 540 m beneath the mountaintop.
Normally, scientists estimate the scale of an explosion by measuring seismic waves that occur immediately after a nuclear blast. But in the North's case they had to make an indirect estimate because it was difficult to obtain seismic data from test site.
"Satellite based radars are very powerful tools to gauge changes in earth surface, and allow us to estimate the location and yield of underground nuclear tests," Sreejith said. "In conventional seismology by contrast, the estimations are indirect and depend on the availability of seismic monitoring stations."
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