north korean nuclear explosion, page-2

Sounds like hot air to me. How can they tell it is nuclear, rather than natural. North Korea lies close to Japan with its' frequent EQ's, and South Korea is not immune to them either.

The bit below is what surprised me...ie that people in North Korea are able to respond to how th w 'quake' felt to them over the internet and onto the US government's own USGS site.

http://earthquake.usgs.gov/earthquakes/dyfi/events/us/c000f5t0/us/index.html