Detonate a 150 Kilotons nuclear bomb 77M underground

[lnsanity]

If I detonate a 150 Kilotons nuclear bomb 77M underground what would be the radius of the E.M.P. effect above ground ? If the nature of the soil change the result than give me a couple of soil example like rock, granite, etc... I was assuming that there would be no E.M.P. effect or very short distance effect but someone is arguing with me there would be one so tell me the truth !

 

[EMPactAmerica]

A nuclear weapon detonated on the surface or underground will generate no HEMP (High-altitude EMP) with long range effects, but will generate SREMP (Source Region EMP), which can be very powerful, but very limited in range, perhaps a kilometer or two. Glasstone's The Effects Of Nuclear Weapons is an excellent official DOD source for SREMP effects.