Electromagnetic Pulse is called EMP for short . EMP is an instantaneous electromagnetic energy generated naturally . Especially when lightning strikes in the sky , the energy that is generated before the lightning strikes is EMP and this energy is very strong. Man- made EMPs are usually made by nuclear detonation. Man-made EMP capabilities were first discovered as soon as the world's superpowers began nuclear testing. Significantly , the Starfish Prime Test in 1982 , where a 1.4 megaton bomb exploded over the Pacific Ocean , damaged electrical equipment 1,400 kilometers away.