This just in, haven’t plotted it yet:
Debris fell into the Yellow Sea at 124E 36N, about 5 minutes after launch.
That’s roughly where the first stage was to land. Could be the 2nd stage didn’t light.
I didn’t see any control surfaces (fins) on the 3rd stage. Since it is very unlikely that they have developed a gimbaled (able to aim) solid fuel nozzle, the third stage was likely liquid fuel.
That would be a step backwards from the last launch and indicates this was a hurried launch.
Correction:
NORAD is calling the splashdown at 165 km west of Seoul, that is well off the planned flight path. Confirms my earlier report that the flash was seen due west of the DMZ.