How Long Would An EMP Last (And Why)?

How Long Would An EMP Last (And Why)?

Exact Answer: 1 Microsecond to 2 Minutes

EMP stands for Electromagnetic Pulse. It can be described as a strong, short jolt of electromagnetic energy. The source of the EMP can influence the aftermath effects of the EMP and the duration of the EMP. The different sources of EMP are lightning, solar storms, nuclear explosions, strong electric & magnetic fields, and many more. 

Understanding the strength of the EMP, many nations have built EMP weapons. EMP has the power to affect large areas and millions of people as it can damage the electric supply & transmission. Stronger EMP can fry out electronics like computers and mobiles.

How Long Would An EMP Last

How Long Would An EMP Last?

Apart from the source of the EMP, the duration (and also the range) of an EMP can be influenced by the spectrum of frequencies, pulse waveform, and components of an EMP. Irrespective of all the factors, EMP doesn’t last for longer durations. The same isn’t true about its effects.

EMP generated from electric & magnetic sources have a short range & duration. The surges that occur in the power line are also categorized as EMP. This EMP has the strength to destabilize unprotected electronic equipment.

The most dangerous effects are due to the EMP weapons. There are two types of weapons that can cause devastating EMP that are distinguished based on the use of nuclear technology. NEMP, also known as nuclear EMP, is a result of a nuclear explosion. The nuclear explosion triggers a nuclear EMP as a secondary effect.

Nuclear EMP has three components named E1, E2, E3. Component E1 has a duration of about a microsecond. It is the strongest component with the most devastating effects. It is capable of damaging computers & other equipment. Component E2 has a duration of 100 microseconds to 1 second, and component E3 has a duration of almost 2 minutes.

There are two modifications of Nuclear EMP. The first one is the high-altitude nuclear EMP also known as HEMP, and the second one is known as the super or enhanced EMP. High-altitude EMP is considered to be fruitful in disrupting the electrical & communication lines. Whereas, enhanced EMP is considered to be more devastating. The duration of these EMPs is less than one second.

Non-nuclear EMP or NNEMP is a type of weapon specially designed to produce devastating EMP as a primary effect. Non-nuclear EMP has a shorter range and is less effective when compared to a nuclear EMP. The duration of a non-nuclear EMP is in the range of microseconds to seconds.

Electric1 to 10 Microseconds
Magnetic1 to 10 Microseconds
E1 Component of NEMP1 Microsecond
E2 Component of NEMP100 Microseconds to 1 Second
E3 Component of NEMP1 to 2 Minutes

Why Would An EMP Last So Long?

Irrespective of the source, EMP travels almost at the speed of light. Considering the range of the EMP, the speed via which it travels supersedes. This results in the EMP lasting for a few seconds. Mostly, the EMP will dissipate its energy almost immediately. The effects may last longer. Possibly, one may have to replace or at least repair most of the unprotected electronic components after an EMP. The strength of the EMP is a deciding factor.

For nuclear EMP, the case is different. EMP is a secondary effect that lasts as long as the cycles of the half-life of the radioactive materials exist. This results in the components of EMP which follow one after the other. The after-effects of nuclear EMP are more dangerous and last longer.

The source of EMP has a great influence on its duration. The E3 component of nuclear EMP and natural solar EMP is caused due to the earth’s magnetic field. This causes the EMP to last longer with the after-effects restricted to transmission lines. Whereas, E1 component of nuclear EMP is caused due to the Compton effect. This EMP component is almost instantaneous, but the after-effects are much more devastating.


EMP is quite dangerous. This has resulted in the development of weapons based on EMP. Nuclear weapons cause an EMP as a secondary effect. The development of non-nuclear EMP weapons & other modified EMP weapons has caused global attention towards EMP.

EMP lasts for seconds only. It has a high speed and may cause damage to transmission lines, electrical & electronic equipment. Depending upon the source of the EMP, the duration & after-effects are highly influenced. 


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10 thoughts on “How Long Would An EMP Last (And Why)?”

  1. I was not aware EMPs are so short-lived. The distinction between different duration components is informative.

  2. The fact about the EMP, irrespective of source, lasting for merely seconds has made me very aware of the potential danger of EMP.

  3. Avatar of Patricia Thomas
    Patricia Thomas

    It is indeed surprising that EMP lasts for a second only. The article has done well to educate me.

  4. I find the source of EMP’s influence on duration very interesting. It’s a crucial part of EMP understanding and not widely known.

  5. Avatar of Wilkinson Abbie
    Wilkinson Abbie

    The explanation of the duration of a non-nuclear EMP was very insightful. The article has done well to elaborate on this.

  6. The distinction between nuclear and non-nuclear EMPs is fascinating. Confirms the efficiency of nuclear EMPs.

  7. I had an inkling of EMP’s speed and duration before. Nevertheless, the article has given a very expansive explanation of this.

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