During WWII, the Japanese send a few subs off the US west coast, attached some bombs to some baloons, and send them up. They pretty much all exploded in uninhabited areas, although a couple did start forest fires.
I wouldn't rule out the possibility of the NKs doing something similar, just to make us think their missile capabilities are better than they really are.
Yep. Sub launched missles. We can watch known land based missle listes for launch signatures, but covering the entire ocean is pretty hard to do. Why do you think we spent so much time and money getting the best submarine fleet in the world if they weren't so darn sneaky.
Anyone know what the NK naval arsenal is like? Do they have ballistic missle subs? are they nuclear or diesle-electric? what about ships that can launched missles (can you fire ballistic missles from a ship?)
I seriously doubt this was launched from mainland NK.