[Poohbah]

I have a copy of Bruce Blair's Strategic Command and Control open to the EMP diagram on page 91. The scenario is a high-yield thermonuclear detonation 62 miles above the Earth, centered on western Nebraska. It would have EMP'd every Minuteman field we had in the mid-1960s (Minuteman launch control centers were not EMP-hardened until the early 1970s). The radius of the 20,000-volt-per-meter ring is 744 miles (coincidentally, exactly 12 times the burst height of 62 miles).

If the 62-mile figure were used, but the blast hypocenter is NYC, the circle would just about reach the Indiana-Illinois border. A 100-mile burst height would probably generate an EMP ring about 1,200 miles across; this would extend to somewhere around Kansas City.

[Travis McGee]

I wonder if the diesel on my sailboat will start? Of course, I could always sail out, in a pinch, on an ebb tide.

[eno_]

A high yield thermonuclear explosion is 2,000-20,000 times bigger than than the largest plausible terrorist nuke.

Only Russia or China could even attempt it. And since no civilian casualties are an immediate result, what is the barrier to retaliation in kind? It's not like the Chinese do military logistics on abacuses anymore.