Seems like a little more than link bait: "South Korea and the US placed their forces in South Korea on alert in the wake of the rumoured blast as reports emerged that North Korea may have yesterday given the US and China advance warning of the test."
Edit - From http://www.nytimes.com/2013/02/12/world/asia/north-korea-nuc...: "Tibor Toth, executive secretary of the Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO), said the seismic event's location was "roughly congruent with" nuclear tests carried out by North Korea in 2006 and 2009."
Edit - From http://www.nytimes.com/2013/02/12/world/asia/north-korea-nuc...: "Tibor Toth, executive secretary of the Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO), said the seismic event's location was "roughly congruent with" nuclear tests carried out by North Korea in 2006 and 2009."