or ( EMP ): ( from the Glossary of Telecommunication terms - Federal Standard 1037C )

1. The electromagnetic radiation from a nuclear explosion, caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the nuclear device or in a surrounding medium. The resulting electric and magnectic fields may couple with electric/electronic systems to produce damaging current and voltage surges. May also be caused by non-nuclear means.

2. A broadband, high-intensity, short-duration burst of electromagnetic energy.

note: In the case of a nuclear detonation, the electromagnetic pulse consists of a continuous frequency spectrum. Most of the energy is distributed throughout the lower frequencies between 3Hz and 30 kHz.


In other words, it's one of the reasons the entire world may be 48 hours from total anarchy.