EMP

How Long Will an EMP and its Aftermath Last

power grid

EMPs: Electromagnetic Pulses. To many preppers, EMPs are seen as the penultimate doomsday event. Be they a naturally occurring phenomenon or the byproduct of man-made superweapons, EMPs are theorized to knock humanity back to an Industrial Age state of being in a literal blink, or perhaps even worse.

By disabling or destroying any electrical device that utilizes a circuit board, an EMP will eliminate virtually every unhardened piece of modern technology. What preppers want to know is how long it will last?

An EMP is both an instant occurrence and an aftermath: EMP itself radiates outward from its source at nearly the speed of light. These waves will interact will electrical devices and inflict damage nearly instantly.

The duration of an EMP aftermath is highly variable depending on severity. Light damage can be repaired in days or weeks. Severe or widespread damage might take years or a decade or more to replace.

Complications

There is more to consider than just the EMP “burst” and its effects, since some weapons that generate EMPs as a secondary effect, like a nuclear warhead for instance, will “sow” electromagnetic interference in the form of nuclear fallout, the “radiation” component of this fallout being, you got it, radio waves.

This manifests as continual disruption of devices that receive or transmit radio waves, and potentially can interfere with solid state electronics like the main pulse.

This effect will be present until the radioactive material has gone though several phases of its half-life or it is cleaned away entirely. Again, replacement or repair of affected electronics will be required.

So while EMPs are typified as a large, wide area event, EMP effects can take several forms and the duration of each is dependent on its nature.

Survivability

The only way to protect functionality is to specially harden the device against EMP by design, an expensive and, frankly, theoretical proposition since most electronics have not been tested against an EMP of the magnitude which is likely to cause a regional or national crisis.

“Isolation” of sensitive electronics is possible with Faraday cages, but again this is beyond the reach of nearly all preppers when it comes to proper testing.

One of the only surefire ways of preventing a total-loss of capability from an EMP is to go “analog”. While not entirely true, as electronics utilizing early vacuum tube technology are practically immune to an EMP.

The electrical potential needed to overwhelm and force a vacuum tube’s receiving plate to feed power in reverse is astounding, and any EMP that is generated close enough to the vacuum tube to accomplish that (one generated by nuclear weapons, at least) would be a moot point since the tube would be destroyed.

The other major factor in determining the duration of an EMP’s practical effects is in the intensity of the pulse itself. An EMP can potentially destroy only the most delicate of electronics, or it can pop fuses and trip circuit breakers. It is capable of being so strong it literally immolates power lines and vaporize conductors. It all depends on its strength.

A comparatively minor EMP may only result in a bunch of burned out consumer electronics heading for landfills. Anything protected by a circuit breaker or fuse and not containing a computer chip should survive and be ready to go when the fuse is replaced or the breaker reset.

Anything subjected to a strong enough EMP that slags conductors and fried electrical systems and circuit boards alike will the stuff doomsday is made of; there is no telling how long it would take to repair such catastrophic damage over so wide an area.

Conclusion

While an EMP is itself over in a millisecond, its effects can persist for weeks or months in the form of radioactive fallout if it was generated by a nuclear detonation.

The damage caused by an EMP will in effect render the world a snapshot to its silent and invisible havoc; depending on the strength of the EMP, anything from minor repair to complete overhaul and replacement of all affected electrical systems may be required, taking years or even a decade or more to fix.

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About Tom Marlowe

Tom Marlowe grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, He has the experience in helping civilian shooters figure out what firearms work best for them.
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8 thoughts on “How Long Will an EMP and its Aftermath Last

  1. Tom,
    I don’t know your background or where you got the information for this article; but, you’ve gotten so many facts wrong I have to take them on and explain them; however, to be honest, not many people have the physics background to understand or really explain an EMP.
    I’ll add more here later today as I get iime.

  2. While I am not an EMP expert, I have worked with electronics for nearly 60 years (vacuum tubes & solid state), including a post college 40+ year career in electronics that included ESD (Electro Static Discharge) testing and FCC compliance testing, as well as designing equipment that had immunity to ESD

    EMPs: Electromagnetic Pulses. To many preppers, EMPs are seen as the penultimate doomsday event. Be they a naturally occurring phenomenon or the byproduct of man-made superweapons, EMPs are theorized to knock humanity back to an Industrial Age state of being in a literal blink, or perhaps even worse.

    There are no EMP’s that originate from a naturally occurring phenomenon and although a CME (Solar Coronal Mass Ejection) can have similar effects, they are limited to long lines (antennas) like power and communications infrastructure and are unlikely to affect any electronic device not connected to a long wire antenna or the power grid.
    The major difference is the frequency (rise time) of the generated pulses.

    By disabling or destroying any electrical device that utilizes a circuit board, an EMP will eliminate virtually every unhardened piece of modern technology. What preppers want to know is how long it will last?

    Actually, most small consumer devices are hardened more than people know.
    They have to endure ESD, that spark from your finger when you walk across the room and also interference from the radio waves emitted from many other consumer devices, like fence chargers, neon lights, LED light bulbs and some HDTV’s.

    An EMP is both an instant occurrence and an aftermath: EMP itself radiates outward from its source at nearly the speed of light. These waves will interact will electrical devices and inflict damage nearly instantly.

    That is true in some instances; but, not all devices in all cases, since it depends on the type of circuit board in the device, the type of case, what kind and how much ESD protection is in the design, and the orientation of the device to the incoming EM wave front.

    The duration of an EMP aftermath is highly variable depending on severity. Light damage can be repaired in days or weeks. Severe or widespread damage might take years or a decade or more to replace.

    Severity will again depend on the device, its orientation, and how much conductive material is there to “receive” the energy.
    I think that most of my systems, including my generator has a good chance of surviving; but, the biggest effect on long term duration and down time, will be the power grid, since it has thousands of miles of power lines to act as antennas that will collect the energy from a pulse and damage the infrastructure, including high voltage switch gear and transformers, some of which are custom built and too large and expensive to be kept in stock.
    Anything you have plugged into the power grid during and EMP is also likely to be damaged.

    Complications

    There is more to consider than just the EMP “burst” and its effects, since some weapons that generate EMPs as a secondary effect, like a nuclear warhead for instance, will “sow” electromagnetic interference in the form of nuclear fallout, the “radiation” component of this fallout being, you got it, radio waves.

    The radiation components of fallout are definitively not radio waves; but, a combination of Alpha & Beta Particles and Gamma Rays, with the Gamma being the only EM radiation.
    If the Alpha, Beta, and Gamma are of sufficient intensity (ionizing radiation) they can ionize the air around them and ionized air can emit radio frequency noise, like that hears on an AM radio during a thunderstorm.
    That radio noise is also what remote lightning detectors use when you see the meteorologists showing lightning activity maps.

    This manifests as continual disruption of devices that receive or transmit radio waves, and potentially can interfere with solid state electronics like the main pulse.

    No it cannot. See the explanation above.
    It can interfere with radio communications; but, has nothing to do with solid state vs. vacuum tube based equipment. I have both and see & hear this clearly during thunderstorms, both local and remote.

    This effect will be present until the radioactive material has gone though several phases of its half-life or it is cleaned away entirely. Again, replacement or repair of affected electronics will be required.

    This is correct; but, once again, the residual radiation from fallout will not damage undamaged or functional equipment, only cause radio frequency interference

    Survivability

    The only way to protect functionality is to specially harden the device against EMP by design, an expensive and, frankly, theoretical proposition since most electronics have not been tested against an EMP of the magnitude which is likely to cause a regional or national crisis.

    This really depends on the device. While most consumer devices are not tested against an EMP specification, they are compliance tested for FCC emissions (a two way function) and for ESD, so small devices unconnected to outside wiring (power lines, cable TV, telephone lines, etc) are likely to be undamaged,

    “Isolation” of sensitive electronics is possible with Faraday cages, but again this is beyond the reach of nearly all preppers when it comes to proper testing.

    A good faraday enclosure for a single device is easy and rather foolproof. Place the device in a cardboard box, with the original container often being the best fit.
    Wrap the box with several overlapping layers of aluminum foil in one direction, Tuck in the foil sticking out around the box, and then wrap the side of the box with cardboard still showing. Ticj this vox on a shelf or in a srawer.

    One of the only surefire ways of preventing a total-loss of capability from an EMP is to go “analog”. While not entirely true, as electronics utilizing early vacuum tube technology are practically immune to an EMP.

    Analog? What does that even mean? I use both solid state and vacuum tube equipment with both analog and digital communications.
    If you actually meant using vacuum tubes, they would be mostly immune to the EMP effects; but, be prepared to have lots of power available, since they are often heavier, use much higher voltages and currents to operate, generating a lot of heat in the process. The weight and power are one reason that solid state electronics have overtaken them.
    OTOH, tube type equipment is durable. I gave some Equipment I built back in the 1970’s that had not been operated in a decade to a friend who is a new ham. He connected it and it was still operating like new.

    The electrical potential needed to overwhelm and force a vacuum tube’s receiving plate to feed power in reverse is astounding, and any EMP that is generated close enough to the vacuum tube to accomplish that (one generated by nuclear weapons, at least) would be a moot point since the tube would be destroyed.

    Destroyed along with its owner and the building where they were hiding due to heat and blast effects of the weapon.

    The other major factor in determining the duration of an EMP’s practical effects is in the intensity of the pulse itself. An EMP can potentially destroy only the most delicate of electronics, or it can pop fuses and trip circuit breakers. It is capable of being so strong it literally immolates power lines and vaporize conductors. It all depends on its strength.

    It is not likely to vaporize conductors; but, circuit breakers and fuses within the power grid may all be subject to tripping &/or failure.

    A comparatively minor EMP may only result in a bunch of burned out consumer electronics heading for landfills. Anything protected by a circuit breaker or fuse and not containing a computer chip should survive and be ready to go when the fuse is replaced or the breaker reset.

    Wow. You don’t seem to understand the rise time of an EMP pulse, that will go right around / through fuses and breakers before they can trip.and can still cause damage, The best option is still to not have equipment connected to outside antennas, like the power grid, cable TV or telephone lines.

    Conclusion

    While an EMP is itself over in a millisecond, its effects can persist for weeks or months in the form of radioactive fallout if it was generated by a nuclear detonation.

    True; but, once again that fallout, while dangerous to living creatures, is unlikely to cause any additional equipment damage, once it is functional.

    The damage caused by an EMP will in effect render the world a snapshot to its silent and invisible havoc; depending on the strength of the EMP, anything from minor repair to complete overhaul and replacement of all affected electrical systems may be required, taking years or even a decade or more to fix.

    Unconnected small items may easily survive; but, the power grids (there are 3) as a national energy provider will likely be damaged and take months or more to repair.

    1. Top, the REAL question is…. With the Carrington event causing telegraph lines to burst into flames what would happen to the wiring and structure of your house in an EMP or CME? Would your house burst into flames?

      1. Thor1,

        With the Carrington event causing telegraph lines to burst into flames

        We need to keep in mind that the telegraph equipment back in the 1850’s consisted only of wire or coils of wire powered by crude Voltaic batteries AKA Voltaic piles, and entire sections of the system were often disrupted or destroyed by either direct or even close lightning strikes, so the energy impressed on the entire system by the CME of the Carrington Event (1859) while damaging, was not unexpected or out of the ordinary for the technology of the day.
        Modern power transmission lines whether the ultra high voltage (300,000-765,000) strung from tall metal pylons (towers) we see across the landscape, down to the distribution lines with lower voltages (7,200-16,000) that run down your street, are continuously assaulted by lightning and the circuits are built to handle that assault.
        Since the rise times of the induced fields from a CME are relatively slow in comparison to that of am EMP, the power grid will be damaged; but, probably not destroyed by a CME, especially since we always have adequate warnings for a CME.
        The point here is that while the telegraph damage from the Carrington event was bad, modern understanding of such assaults and how to mitigate them are significantly better than in the 1850’s, making the Carrington event example a bit of a straw man.

        what would happen to the wiring and structure of your house in an EMP or CME? Would your house burst into flames?

        Once again the answer as always is ”it depends”.
        A battery powered radio sitting in a drawer of a metal desk or filing cabinet or potentially just sitting on the counter may not be damaged; but, if connected to an antenna, either a real outside antenna or the power line to the house, it stands a better chance of being damaged.
        The energy from an EMP or a CME is basically a radio wave that needs to impinge on / encounter a conductor to be converted to a current & related voltage. If your house was off grid and not connected to the power grid (a large antenna system), then the wiring in the house would not likely”capture” enough energy to do any damage; but, when connected to the grid, that large field of wires can act like antennas to capture energy and deliver it to your house.
        Even a grid connected house however may not be damaged or damaged much, since the incoming power line passes through a breaker (or fuse) box, that may stop or reduce the transient. You may also have a whole house surge protector that can alleviate / absorb some of the energy. If you use outlet strips with surge protectors those can absorb / reduce the energy even more.
        Finally, appliances like computers, televisions, and nearly anything powered by the system can take that final assault, often giving up their lives to save the house.
        We have had one bad lightning strike here years ago and the only things damaged were a modem, some lighting controls, and a completely fried well pump, where the lightning found the best earth ground in the house. Nothing else was damaged, so whether the cause is Lightning, CME. or EMP, the damage is simply too hard to predict; but, unlikely to burst into flames, unless one of the devices caught fire as it was overloaded and dying, a real possibility.

  3. I claim no expertise in matters of what an EMP would or would not do….but I feel fairly confident IF the grid goes down for any extended period….says weeks…..the death rate in the US would be astronomical. There are simply too many people that live day to day in terms of food and water supply, and after 1-2 weeks, social chaos would result.

  4. Look at what’s happening in California, with PG&E, doing the shut downs, if that’s not an eye opener, then I simply don’t know what would be and now with California, Oregon, Washington state, wanting to ban natural gas, and have us all depending on electricity, there is simply not enough electricity to go around and to add it will take year’s upon year’s is absolutely ridiculous.

  5. All this talk of Emps makes my kobold want to nibble the goblin.

    I wonder if any Kobolds ever had Relations with goblins. is that how emps are made?

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