The Interesting Story About North Korea

If you've read or watched the news you probably know about this already. If not, here's a synopsis:
September 9th is the Anniversary of North Koreas founding. Like our own independence Day, they celebrate with explosions and displays of military power. (In America, it's called air shows) Everybody loves it.

Ok, so on Thursday, South Korea reported an explosion in North Korea. They claimed there was a mushroom shaped cloud 2.1 to 2.5 miles in diameter. They claimed there was a crater that could be seen from a satellite. And they claimed seismic activity was consistent with two explosions; one at 11 p.m. Wednesday and on at 1 a.m. Thursday.

NEIC doesn't list any recent earthquakes in North Korea. I couldn't find any satellite images featuring a new crater. Doesn't mean nothing happened. Just means I haven't found evidence with my little pc and dial-up connection.

And there's the question of censorship. If this (these?) blast(s) happened on Wednesday/Thursday, why did South Korea wait until after Sept. 11th to announce it/them?