North Korea third Nuclear Test(inside story)

South Korean defence ministry predict that North Korea has launch his third Nuclear test here on tuesday,
Moreever the South Korean official says that they percieved that their is some earth quick so they mobiliZed their armed forces for any unpredictable situation, but after some time earth quick monetry cell reported that this was not an earthquack this was nuclear explosion held by North Korea.
Remember that kind of two test has already been done by North Korea in 2008 and 2009 and thats vibration was also just like that. And their magnitude was 3.9 and 4.5 respectively, so we can say that this is more forward step by North Korea toward Nuclear power. Today its magnitude was 5.2 by the Japanies monetering agencies.
On the other hand if this is true than nost of the analyst saying that this is threat for the common security of the world.
Now North Korea also going to be part of the Nuclear world.