South Korean seismographic readings have indicated that North Korea has conducted its third nuclear weapons test at 0257 GMT on 12 February in the North Western region of the country. The underground test of a fission class weapon is estimated to have had an explosive power of 6-7kT – equivalent to 6000-7000 tons of TNT. While this is only about a third of the power relative to the bombs dropped on the Japanese cities of Hiroshima and Nagasaki during World War 2, it does respresent and increase over previous tests in 2006 and 2009 which were 1 and 4.7kT respectively.
Western experts are more concerned over North Korea’s claims that the weapon was much more compact that previous devices, indicating that it may be a forerunner of a ballistic missile-carried nucleaer warhead. North Korea’s satellite launch in December 2012 using its Taipo Dong 3 missile-based Uhna 3 launch vehicle showed it had a theoretical ability to throw small warheads over thousands of kilometers, threating most of its neighbours in the South East Asian region including South Korea, Japan and China.
Western nuclear experts are also concerned that the latest North Korean nuclear weapon test was of a device that is Uranium-based rather than one using plutonium as its fissionable material (as was used in North Korea’s two previous tests). North Korea has unlimited supplies of Uranium and only a limited supply of plutonium.
Comment by David Todd: The news is likely to be a spur to US development of more advanced longer range versions of the US Navy (and Japanese Navy) cruiser and destroyer-based Standard Missile SM-3 anti-ballistic missiles (ABM) which can.intercept balllistic missiles during their unpowered mid-course trajectories.