I can put enough C4, or whatever it is that the NKs use, under ground to make “like” a nuke tremor,
Could it be that they dropped the latest general to diss the Dear Leader down a hole and then plopped some dynamite on top?
More like the free rail car loads of hundreds of thousands of tons south Korea gave them of fertilizer.
That wouldn’t create the signature isotopes.
*and*
1.300 kT=72 tractor trailers' worth
*and*
WC-135 Constant Phoenix departs overseas.
Conventional explosions don't produce novel and unique radioisotopes.