EMP threat is over rated via a paper by Nobel Prize physicist Jack Stienberger.
https://www.documentcloud.org/documents/272552-the-electro-magnetic-pulse-produced-by-a-nuclear.html
Major math in that paper.
That is what some of us on FR have been saying for weeks.
Now a nuclear mine detonated under a Carrier Task Force, now that is a real possibility and well within NK capabilities.
If an EMP was that good a weapon, the US military would have tested it on somebody by now.