Can a nuclear test be shielded?
Yes. Nuclear bombs produce weaker shockwaves than equivalent conventional explosions because more energy goes into generating heat and radiation. Seismologists believe the North Korean test yielded the equivalent power of 550 tonnes of TNT, which suggests a 1-kilotonne nuclear device was tested. But the test bomb may have been at least five times larger if it was partly “decoupled”, a technique used to deaden the seismic shockwaves by exploding the bomb inside a chamber instead of nestling it close to the surrounding rock. Theoretically, it is possible to muffle the shockwaves produced by a nuclear explosion 40-fold if it is completely decoupled.
