EMP? Don’t Lose Any Sleep This Year

The subject of EMP is red-hot this week, as a new novel about America after electronics – ‘One Second After.’

Again, I haven’t read the book (yet -I will) and I’m no expert on the effects of nuclear weapons. But some amateur math confirms the gut impression that a small (10 – 20Kt) weapon isn’t going to have a massive national impact.

I’m bringing forward a post I did back in 2006 below so you can check my math:

OK, I’m looking at the likely effects of EMP and doing the classic blogger thing of dipping into serious issues as a rank amateur. But I may be right, and if not, I’ll trigger a darn interesting discussion.

TG works close to the Los Angeles Public Library, and we have a deal where I’ll find a book I’m interested in, email her the catalog link, and she’ll pick it up and bring it home for me. The Department of Homeland Security is doubtless interested in her borrowing habits…

Today, she brought home Glasstone & Dolan’s “The Effects of Nuclear Weapons,” Third Edition.

Here’s what I learned. To maximize EMP effect, the weapon has to explode at an altitude of over 19 miles – there’s a dramatic increase in the amount of gamma converted to electricity at that height. The EMP effect is generally limited to the line-of-sight to the weapon, and does diminish somewhat as the weapon explodes at greater and greater heights – because more of the gamma radiation which is converted to electrical energy by the atmosphere is radiated upward.

The end result of my quick Excel calculations is the energy per square mile would vary between 0.03 joules/mile for a 10KT weapon detonated 15 miles up, with an effective radius of 350 miles and 17,800 joules/mile over an area with a radius of 1500 miles for a 1 megaton blast at 300 miles up.

Now this may sound like a lot, but recall that a lightning bolt has about 109 – 1010 joules.

And a Shahab-1 has a maximum height of about 55 miles.

Here’s some math [formatting fixed by Joe]. There are three cases for calculating EMP; ground burst, mid-level air burst, and high-altitude burst.

High-altitude is defined as over 19 miles; there the effect is far greater (more of the gamma radiation from the weapon interacts with the atmosphere, creating a plasma, and thus the burst of electrical energy).

For a high-altitude burst, about 10-2 of the gamma radiation is transferred to EMP. For a mid-altitude burst, it’s about 10-7. For a one-megaton weapon, the total energy output is about 4.2 × 1022 ergs. About 3 × 10-3 of that becomes gamma radiation, or 1.26 × 1020 ergs.

At low altitude, this yields about 1.26 × 1013 ergs, at high altitude, about 1.26 × 1018.

In joules, that’s about 1.26 × 106 for low altitude, and 1.26 × 1011 for high. It’s linear to weapon yield, so a 10 KT weapon would have 1.26 × 104 at low altitude and 1.26 × 109 at high.

But that area is dispersed over a wide area – the total energy matters, but the energy density matters as well (total energy matters more in effects on long conductors, like power lines).

Even at very high altitudes, the EMP effect is limited to the ‘tangent radius’ of the blast – the height at which it goes below the horizon. So at a 15-mile blast height, the radius looks like 350 miles. At 300 miles, it would be about 1500 miles.

So, as above the energy per square mile would vary between 0.03 joules/mile for a 10KT weapon at 15 miles, with an effective radius of 350 miles; and 17,800 joules/mile over an area with a radius of 1500 miles for a 1 megaton blast at 300 miles.

What’s my point?

When Iran or whoever can develop weapons with yields in the megaton range, and the ability to deliver them to a height of 300 miles, we need to worry about EMP. Until then, I’d say we’ve got other problems.

Corrections and comments welcome…

47 thoughts on “EMP? Don’t Lose Any Sleep This Year”

  1. You havent accounted for “Compton Scattering”:http://en.wikipedia.org/wiki/Compton_effect in the high atmosphere.

    Essentially the earths magnetic field bounces gamma radiation back to the earth trapping the energy in the atmosphere, spreading the energy radially instead of spherically. These gamma rays interact with free electrons ionizing the atmosphere and producing an electromagnetic field hundreds or thousands of miles in diameter.

    ” Ironically, this nuclear research led to an unexpected demonstration of the power of the Compton Effect, and spawned a new type of weapon. In 1958, nuclear weapons designers ignited hydrogen bombs high over the Pacific Ocean. The detonations created bursts of gamma rays that, upon striking the oxygen and nitrogen in the atmosphere, released a tsunami of electrons that spread for hundreds of miles. Street lights were blown out in Hawaii and radio navigation was disrupted for 18 hours, as far away as Australia. The United States set out to learn how to “harden” electronics against this electromagnetic pulse (EMP) and develop EMP weapons ….”


    This isnt something to take lightly. We’ve talked a great deal already about “Starfish Prime”:http://en.wikipedia.org/wiki/Starfish_Prime but i urge people to check out exactly what happened when a 1.4 megaton bomb exploded 400 km in the atmosphere. Aside from turning out the lights and radios in Hawaii 1000 miles away, it created a false Aurora Borealis visable from 2000 miles away, affected communications as far away as Australia, and “mucked up”:http://www.lightwatcher.com/chemtrails/Papadopoulos-chemtrails.pdf#search='emp%20mev‘ the Earths radiation belts for years and knocked out several satellites. Recall this was done at a location about as remote as we could manage on the planet. If this test had been carried out over Nevada the entire West Coast would have been blacked out.

    Now you are correct that altitude is the critical factor here, but even a 500 kiloton weapon detonated at 500 km would devastate the country, which NK rockets are capable of right this moment. The payload is only a matter of time. Dont forget the cascading effect of overloaded power plants all over the country. Remember what happened a couple years ago when the grid went down.

  2. #1 (Mark):

    500 kT to 300 miles over US soil is still pretty challenging with today’s new-nuclear-club tech.

    It is certainly the case that very-high-airbursts intended to inflict EMP have vanishingly-small problems with CEP (targeting accuracy). But half-megaton warheads that can be lofted that high with DPRK-available boosters are most likely going to be thermonuclear, not plain ol’ nuclear. So there’s probably a little grace period before DPRK can do that.

    “Devastating” is in part a psychological declaration. I hope you are aware of that.

    Example: If the entire island of Manhattan were swept by a magic fallout cropduster and had a background radiation 1000 times what it does now, it’d still be habitable. But you’d want to populate it with people likely to die of other causes before the increased cancer rate caught up with them. And that’d probable freak people out; in part because the media-entertainment-lifestyle complex is designed to create sensations.

    Devastating? Maybe. Maybe not. Certainly creepy as hell. Ionizing radiation is generally creepy because people can’t sense it.

    It’s really hard to calculate the risk profile for something like this. There are too many variables to Monte Carlo it from first principles. Or so it seems to me.

    If we were Moties, we’d have a large historical sample to draw from. ;\

  3. Just why would (lets say) Iran use a Shahab-1 when they have perfectly servicable Shahab-4s? Mount five Shahab-4s into five launchers inside five freighters. Have each launch a shot for maximum altitude from America’s east coast, west coast, and Mississipi delta area. Add another from the Mediterranean over Europe, and another over Japan. What a mess that would be. Military systems might survive just fine but so much else wouldn’t. What yield would be possible for (lets just say) Iran to produce now? France back in the 60’s was making nuclear bombs in the 60KT plus yield range, I don’t see why Iran couldn’t make one at least that large. Shahab-4s have a range somewhere around 2,000Km and a payload of about 1,000Kg. That would translate into a pretty good warhead delivered 500Km+ inland at a very respectable altitude at apogee. That translates into a lot of fried electronics everywhere.
    Honestly, EMP is the threat that is most worrying to me. A ballistic missile shield that could knock down just a few missiles per coast would suffice against such a threat. Its just always so much cheaper and easier to break things than build and protect them.

  4. Let me do a real world calculation and see where it leads.

    Let us suppose an energy density of 50,000 joules/sq mi.

    Chips these days are protected from human induced lightning at levels up to 2000 volts on a 100 pF capacitor. That is it can handle an pulsed energy level of 62.5 microjoules if we say the no damage threshold is 500 volts.

    50,000 joules/sq mi = 1.8 microjoules/sq ft.

    Which represents a 100 pF capacitor charged to about 200 volts.

    So a circuit board that is unplugged will probably sustain zero damage. Especially if it is bagged. And don’t forget I’m assuming all the energy will be concentrated in one input junction.

    The problem is items plugged into an antenna. i.e. the power line. Given the number of surge protectors etc. you will get some damage i.e. a certain percentage of eqpt. (.1 – 20%) might be damaged.

    It will be a problem. It will not be the end of civilization as we know it.

    What you would need to do is to lob a bomb. Wait an hour for people to move their eqpt. Lob another bomb. etc. Each time with diminishing returns.

    Tactical military eqpt will be unaffected except for flukes. Military eqpt is protected against battle field nukes.

    As A.L. points out. The energy density is rather low. Sunlight is about 100 joules/sq ft every second. The frequency of sunlight is in a range where it does no electrical harm to circuits. Heat is another matter.

    The conventional EMP bombs work only in a very local area.

    Like the “dirty” conventional bomb – the threat of EMP is over rated. It might be a problem if detonated over a city. But then the blast might be more important, eh?

  5. BTW re: Tom Holsingers post

    Where he states:

    So the U.S. government has a different opinion of EMP effects than M.Simon. So do lots and lots of real experts.

    All of whom could be wrong simultaneously.

    Or M.Simon is.

    The design directives for EMP resistant eqpt that I worked with were provided by the U.S. Government.

    What you have to consider is:

    If you are looking for funding – exagerate the problems. Everything is worst case.

  6. I like the antenna question.

    Antennas are designed to recieve signals on the order of .001 w/sq meter. EMP could be 10,000,000 w/sq meter. Pretty scary.

    That would be about 10 orders of magnitude in energy. Huge. What would the difference in voltage be? The square root of that. 5 orders of magnitude. A difference of 100,000. Still pretty big.

    The typical reciever is designed to work well with a signal level of 1 millivolt. 100,000 times that is 100 volts. Which is much less than the typical static protection of your typical antenna circuit.

    As to fly by wire aircraft. I worked on the A-320. Our particular piece of eqpt was designed to take a direct litning hit on the aircraft in close proximity to the eqpt. and at worst go through a two second reset.

  7. This is from the previous EMP discussion on the links provuded upthread:

    All microprocessors are subject to damage and destruction by ungrounded handling via electrostatic discharge. Which is another name for the normal static electricity you get from walking across a carpet.

    The induced electrical pulses from an EMP signal are millions of times stronger and faster.

    Lightning protection isn’t protection from EMP.

    The microprocessors in American military fly-by-wire systems have faraday shielding against the signal pulse of an EMP signal. It costs a lot of money and a lot of testing time in military grade non-nuclear EMP generating facilities to get that level of protection. It also takes on-going maintenance and testing to keep it effective.

    So the fly-by-wire systems of a commerical aircraft do not have that level of protection. It costs too much money and there is no commerical need for such protection nor FAA or EU regulatory requirement that there be any.

    The results of a commerical jetliner fly-by-wire system getting hit by EMP in flight will be lethal to all aboard.

    Assume 300 wide body fly by wire passenger jets are over the Boston to Washington flight corridors when a Iranian freighter launched Shalab-1 lobs a 15 kt nuke 20 plus miles over the Bos-Wash megaplex for an EMP attack.

    Every plane in that air space looses all of its its FBW controls simultaniously and goes down with 100% deaths of those on-board. The average per plane is 100 people. That is 300×100=30,000 deaths the first five minutes after the nuclear EMP device goes off.

    This also does not include the casualties on the ground from the impacting planes nore the problems of fire fighting without power or modern telecommunications to coordinate emergency services.

    Here are some of the comment links to chew on:




  8. Mark –

    The Compton scattering is why a high-altitude (19miles+) burst has a greater EMP effect than a surface blast or low-altitude blast – it’s already in the math.

    I’m with you; a 1.4 MT weapon would have some significant effects over a 500 – 1000 mile radius.

    A 14KT weapon woiuld have about 1/100 of that effect. As noted, when we think the Bad Guys can make a 1MB weapon, we need to be pretty concerned.


  9. Trent,

    The eqpt I designed actually had to pass the gvmt tests.

    The threat is exagerated for political effect.

    BTW want to check the frequency range of the human spark generator? Turn on your AM radio to a clear spot on the band and do some carpet rubbing. You too can be a radio transmitter.

  10. BTW the machine model spark generator when used (no resistor to limit the rise time) generally passes a threat level of 500 volts. For almost all semiconductors these days. For one junction.

    BTW circuits are much less susceptable when soldererd to a board. You then generally have numerous components sharing the energy.

    I’m not saying the problem is zero. Let us just say that I’d expect damage no worse than Katrina and probably much less.

    Some aircraft might fall out of the sky. Maybe.

    Some equipment will definitely get damaged.

    You also have to look at the Hawaii results. If it just hit the one island there may have been some type of waveguide or other directional effect.

    And then you have the fact that salt water is a good conductor. Which means much lower propagation losses for low frequencies. By an order of magnitude aproximately.

  11. (to TARIK’s article, which seems to have its comments blocked. *Joe – can you move this to that article? I took a long time to compose it, and I would like it as a comment!!!*)

    Geez! You’ve written a bloody book!!! Well, bravo, old bean.

    However, nowhere did you mention unsustainable demographics! Unlike “Dark Africa” (a euphemism I like, as it covers the whole of sub-Saharan Africa as a single swath), greater Islamic Arabia hasn’t had undue pressure from rampant disease, pre-historic animism, universal ignorance or hyper-Balkanization. Yet, it *has had the population explosion*.

    It is surprisingly hard to show that the optimum curve for individual prosperity tracks closely to moderate population growth combined with comprehensive industrialism and progressive intellectual accomplishment, but the ObviousMan knows full well that they are linked. When academic excellence languishes, society falls into Midaevelism; when populations outstrip resources, employment becomes formulaic, vacuous and at best nominal – and spotty. When industrialism loses its connection with the desire for a more comfortable lifestyle, for technical civic esthetics, for admiration of the ‘well oiled machine’, then its host society finds it has naught to trade with the world for things of value and interest that augment their own production. In short, society languishes.

    Note here that I’ve not even mentioned Islam or the Muslim Mind in all this: I do not believe that there is a need. I think that the problems of the culture rest *first and foremost* on the trifecta of defeat that the pan-Arabian culture has ‘earned’. But 200 years back and moving forward, the almost comically backward North Africans and Middle Easterners were ripe for colonialism – and so they were colonized. It has been argued ever since that colonialism stole the verve from the heart of Islam, and its predicament is Opus Prima of said European jackboot-on-the-neck.

    Let’s say it is so. And then?

    And then it is concommitant on us to also admit that the post-colonial greater Arabian has had historically extraordinary freedom to mould his society, to either continue in the way brought to the seething masses by the European colonials, or to invent their own new sovereign enterprise.

    But lo, not so. The issue is exactly as that quote in the preface,

    _No wonder the war ended in defeat, not victory,
    For we waged it with all the Orient’s gift for oratory, With quixotic hyperbole that never killed a fly, Fighting in the logic of fiddle and drum. (Nizar Qabbani)_

    This is acknowlegement of cerebral inconsequence, taken civilisationally. It points to _why_ Persia once was the greatest reservoir of Mathematics on the planet, yet fell far, far, far behind within only 300 years. It points to _why_ the Arab on the Street is hyper-aware of all the geopolitical “wrongs” that provide ample fodder for the Tea House, but also implies that the sin is one of inaction, inconsequence itself.

    Combined with:

    – We have donned a thin veneer of civilization While our soul remains mired in the Dark Ages. (Nizar Qabbani)_

    Nizar observes that the Arab is profoundly sentimental in the soul, that the culture can look (somewhat) like the model first imposed upon them by the Colonial West, and then more or less kept up by their own hand – but its superficial depth is the issue.

    Now, take these and follow them to completion:

    – Western medicine has all but eliminated rampant mortality
    – The Arab societies are under enormous demographic pressure to expand
    – The _oil wealth_ is diminishing per capita in turn
    – Industrial and civic “output” are at all time lows in the Arab world
    – Poverty is extraordinary, relentless
    – Islamic ‘communism’ – sharing, tithing, charity is keeping the people alive, but barely
    – On an individual level the future is bleak
    – On a societal level, the future is frightening
    – On a civilisational level, the question of “a future” lies without answer.

    So, then?

    Islam’s communist charity and poor-adoptive life philosophy answers the impoverished common man’s questions: _Why are we so damned poor? What is the meaning of life and existence? How do we maintain a modicum of Honor and Pride in spite of society’s failings?_

    It is thereby no surprise whatsoever that Islam’s Imams are in the ascendent – there is almost no other possibility when a civilisation is stultified by their own visionless plodding, their own rapture with ignorance, and their untenable pursuit of demographic growth. The pressure under the lid must be extraordinary, and the images of the West, through television, magazines, movies and the media must be *absolutely dementing* to the unwashed populus.

    It must be the West’s fault.

    Ergo et sum, nolo sequitore.


  12. You really need to work on your information retrevial methods. Most libraries have photocopiers that take cash( .10 to .20 cents a copy). Whatever you do don’t check the book out, thereby tagging it with your name, just copy it, a high resolution digital camers work even better, and there is some chance of using OCR software to automate reformatting, people do it now with cell phone cameras and magazines they don’t wanna buy, it’s called digitsal shoplifting

  13. The question, “what size and weight warheads could the Iranian regime put on missiles they own or are developing?” is amenable to technical analysis. There is one at “Arms Control Wonk.”:http://www.armscontrolwonk.com/948/iran-the-bomb-2-irans-missile-capabilities It looks like it will be difficult for the Iranians to load their heaviest-lift missile with their lightest, most compact bomb, and have it fly terribly far. They offer this quote:

    bq. According to the Pentagon officials, the Shahab-3 will have a range of between 800 and 930 miles and will be capable of carrying a 1,650-pound warhead; the Shahab-4 will include improved guidance components and can travel up to 1,240 miles with a warhead weighing up to 2,200 pounds.

    “Warhead” in this passage apparently means “payload”; where other components might require about half of the weight and space.

    But note the contribution of commenter John Field, who says

    bq. Obviously, this is a hard thing to estimate. Yet, I always come out that they could do pretty well – that is if they got their act together – which is a big if.

    bq. Consider, at least, the following observations :

    bq. [snip]

    bq. The world is awash in technical talent. It is everywhere. Yet, it remains an unsolved problem to design effective organizations. Estimates of Iranian technical capability will always be ‘fat-tailed’ for this reason – we are measuring the wrong figure of merit. Yet, in America, the land of high infant mortality and also highest MRI machines per capita, it is a mistake we are very prone to make.

    bq. We need to focus our efforts on preventing them from fielding an effective organization. That is the key. And injecting confusion and disorder is the path. This is why despots fail.

  14. I agree, M Simon. Much of today’s electronic equipment is already hardened against overvoltages, and surge arrestors are widely used. The power grid would very probably be knocked out, but generating plants could begin to be spun and lines connected within hours, as long as the grid control survives the attack.

    Some planes may fall, but beyond that my greatest concern is about control systems in industrial plants, especially chemical ones.

  15. AL is right about the threat probably not being imminent (unless there is quite a bit the CIA hasnt ferretted out- i dont even want to think about that). On the other hand once a certain threshold of technology and deterrence is passed (which in NKs case it may well be) it would seem to me the threat becomes inevitable. Once a nation has an atomic arsenal it would see to be only a matter of a time (historically a shockingly short matter of time) before they advance to h-bombs if that is there goal. If Pakistan, for instance, decided they wanted to invest in thermonuclear weapons, what would/could we do to stop them at this point?
    The bottom line is we need to be concerned with this threat now, not because the lights are going to go out any time soon, but because it will be to late to do anything about it once the horse is out of the barn. We will in many ways be at the mercy of our enemies (or their sanity).

  16. AMAC,

    The Iranians do not have to use Fission-implosion designs. Gun type fission designs of less than 600 lbs weight and 15 kt performance were available in 1953.

    The Mk-9 280 mm nuclear shell was test fired in 1953 during the Operation Upshot-Knothole nuclear weapons test program.

    This is the entry on the weapon from the Global Security web site.


    bq. W9 / Mk.9
    W9 T-124 280MM AFAP

    bq. Steps were also taken to develop Army weapons capable of delivering atomic weapons on the battlefield. The first weapon to appear was the mammoth 280mm gun. Since the 280mm gun had already been designed, the major developmental problem was evidently the design of a stable, rugged and relatively small atomic round that could be fired by the artillery. With reductions in size and an increase in the variety of yields, production of such a round soon became possible.

    bq. A live test of the Mk-9 fired from the 280mm cannon was the 15-kiloton GRABLE test conducted on May 25, 1953, as part of Operation Upshot-Knothole. A single test shot was fired seven miles at the Nevada Test site. The Army successfully fired an atomic shell from the World War II vintage 280mm gun, which detonated 160 meters above ground. The resulting 15 kt GRABLE explosion not only symbolized the addition of an awesome new weapon to the Army’s arsenal, but also symbolized the true beginning of the atomic era for the Army. This shot was the first detonation of a gun-type atomic bomb since the bombing of Hiroshima on 06 August 1945.

    bq. Operation Upshot-Knothole at the Nevada Test Site consisted of 11 atmospheric tests. There were three airdrops, seven tower tests, and one airburst. Operation Upshot-Knothole drew a great deal of criticism as resultant fallout levels produced increased offsite radiation exposures. About the time (afternoon of 26 May 1953) the GRABLE debris cloud segment stretched between the 5.6 and 9.2 km trajectories was carrying the higher portion of the radioactive cloud across the east coast (over Maryland), a violent hail storm occurred at Washington, D.C. Hailstones collected from this storm were tested by the U.S. Naval Research Laboratory there (Blifford et al. 1953) and were found to contain high concentrations of radioactive fission products, particularly high in their centers. High concentrations of radioactivity were also found in the air near the surface, undoubtedly carried to the ground by strong vertical air currents associated with the thunderstorm.

  17. Mark (#19)

    _it would see to be only a matter of a time (historically a shockingly short matter of time) before they advance to h-bombs_

    I disagree. In the Western world only the Americans have developed them. For instance, De Gaulle tried to develop them during the sixties, expending a lot of money with no results. Finally Nixon and Kissinger gave to the French Government critical data in 1969. It seems that the Chinese were also interested in American advances according to spyonage issues in Los Alamos Natlabs…

    See how inertial confinement to achieve fussion is studied in the States and not in Europe, where the low density Tokamak’s and Stellarators are the spearhead in _civil_ fussion research. In my opinion a sign of lack of expertise in that area.

    A fision bomb can be built by any industrialized nation but things get very complicated when we talk about a thermonuclear device.

  18. bq. BTW the machine model spark generator when used (no resistor to limit the rise time) generally passes a threat level of 500 volts. For almost all semiconductors these days. For one junction.

    bq. BTW circuits are much less susceptable when soldererd to a board. You then generally have numerous components sharing the energy.

    bq. I’m not saying the problem is zero. Let us just say that I’d expect damage no worse than Katrina and probably much less.

    bq. Some aircraft might fall out of the sky. Maybe.

    bq. Some equipment will definitely get damaged.

    I said this is the previous thread we had on EMP and I will say it again.

    I don’t know how many fly-by-wire (FBW) jetliners you have been on, but every single one I have been on has you shut down electronic devices in take off and landing because of the threat of a spurious signal impinging on the FBW bus.

    EMP is orders of magnitude more powerful and faster than a I-pod or Blackberry bleed off signal

    As for you expertese versus mine, I’ll go with the practical hands on experiance that I had early in my career. The quality validation of military aircraft harnesses and their testing requirements was where I lived, professionally.

    The USAF E4B airborne nuclear command and control plane and Air Force One do not share any of the flight harnesses of a commercial 747 due to EMP requirements.

    The difference between EMP shielded military aircraft wire harnesses and commercial wire harnesses are not just faraday shielding and a special ‘pass thru package’ which are financially significant in and of themselves.

    The military specification EMP shielded harnesses are built at military rates of procurement rather than commercial (think tens versus thousands) and have a 100% testing requirement versus lot sampling or FAA/ISO certification of the manufacturer.

    Military EMP shielding also requires periodic maintenance to maintain their shielding capabilities.

    Every unshielded harness on an aircraft is what amounts to a huge antenna for gathering and concentrating EMP to send it into the electronic devices and controls attached to them.

    I would also hate to think of the sparking that would be induced off of chaffed unshielded harnesses running through other parts of the plane — like, say, a fuel tank — would do.

  19. A.L.,

    It’s not a threat from Iran yet because they lack the necessary warhead technology. Their puppies are too big and fragile to work on ANY missile, let alone the missiles they have.

    IMO they’ll need years of testing and development just for the warheads. The problem is that China might sell the mullahs the required knowledge and technology before the mullahs are kicked out by the Iranian people.

    This need not be done directly – China could sell it to Pakistan, who sells it to North Korea, who in turn sells it to Iran. That is how Iran acquired the knowledge to build the big & fragile nukes even Mohamed El Baradei, director-general of the United Nations’ International Atomic Energy Agency, thinks they can build.

  20. On my website, I recommend Israel using EMP to stop A-bomb development in Iran. Israel has H-bombs, which properly positioned, would knock out unshielded electrical and electronic devices over a (perhaps too) wide range.

  21. A.L.
    Nice analysis but I think it misses the mark in one important way. EMP actually has 3 components:
    -E1 is the “electromagnetic shock”. This has the ability to impair or destroy many protective/control mechanisms.
    -E2 is similar to lightening in its effect. It’s only a problem because it comes a fraction of a second after E1and protective/control mechanisms may have been taken out by E1.
    -E3 is a slower, longer duration pulse that impacts the transmission lines.

    Each component causes damage; latter damage may be increased as a result of previous damage. So it’s not a straight matter of joules. (all that cribbed from the commission report).

    Iran has thought about this:
    An Iranian political-military journal, in an article entitled “Electronics To Determine Fate Of Future Wars,” suggests that the key to defeating the United States is EMP attack

    They appear to have tested the launch profile:
    Some of Iran’s tests of its Shahab-3 had been terminated before the completion of their ballistic trajectories, that is, exploding in mid-flight by what appeared to be a self-destruct mechanism. Iran has nevertheless described the tests as fully “successful.”

    The range of the Shahab-3 is 1200 km. The ideal height for an EMP blast is 500-600 km. (I know – range does not equate to altitude).

    Iran has already testing launching missiles from cargo ships.

    Maybe it is a stretch to connect those dots but it certainly seems reasonable that at least the Iranians may think it is a serious threat.

    I’d suggest reading the Executive Summary by the commission put together to study this if you haven’t already.

    I certainly hope that you (and M.Simon) are correct. I am not an expert in any of this – but I have read a lot of disturbing info on it. Maybe the threat has been exaggerated to get funding as suggested. I hope so.

  22. Trent,

    You have to shut down your electronics not because it might damage eqpt. The reason is because the eqpt might give erronious readings. Or it might possibly interfere with ground communications.

    Don’t forget the planes are being hit with megawatt pulses of microwaves from the airport radars. During takeoff.

    I worked on some of the fly-by wire black boxes (generator controls) for A-320. We hardened that stuff pretty good (both hardware design and software recovery) because we hate killing customers. Bad for business.

    And if the danger of damage is so great how come you can turn the stuff on when you reach a certain minimum altitude?

    Fly by wire is fairly robust. All the communications wiring is twisted shielded pairs. The control stuff is also shielded with somewhat less care because it is low frequency and low impedance and software “debounced”. A temporary upset of even 100 milliseconds is not going to cause problems.

    I know people love to find stuff to be afraid of. EMP is probably less of a threat than another hurricne. And that is providing the mopes can get a decent sized device on a missile they actually own.

    under 100kT – EMP strictly local
    under 1 MT – if used to cover a large area – limited problems. if used to cover a small area – could wipe out a lot of electronics and transmission lines.

    Single bomb coverage of the USA would need to get to the 10 to 100 MT range before you could do serious damage to a wide area. Even then it might only knock out 50% of the grid and electronics. That is going to hurt. It might take as long as a year to bring things back to normal. OTOH it might only knock out 10%. And take only a few weeks to restore function.

    All I can tell you is that I have build radio front ends for aircraft HF sets – which BTW are the most vulnerable. We have all kinds of tricks like low capacitance tranzorbs, spark gaps, etc. Now I admit it was for mil stuff. However, commercial stuff is built to the same specs. Why? Well it is good practice and our aircraft fleet is part of the reserves when necessary in time of war.

    The most common ordinary danger to the front ends is a guy rubbing his foot on the carpet. We protect against that. The most common extrodinairy danger is a direct lightning strike on the antenna. We protect against that. The EMP threat level is 2X to 3X lightning – worst case from a close in strike – after all if the blast is going to get you no need for EMP protection.

    What that says is – because designers like to overdesign against threats – most aircraft eqpt will do OK. Because aircraft designs require no single point failure there is more than adequate defence if all systems are functional.

    What the military designs to is such that an EMP pulse will destroy functionality in less than one piece of eqpt. in 1,000. Ordinairy aircraft might experience 1 failure in 50 maybe. Probably one catastrophic failure in 500 maybe. Which means maybe zero, one, or two commercial flights fall out of the air.

    The main difference is testing. Commercial aircraft are only tested against the lower threat level. That does not mean the less tested commercial stuff will fail.

    The EMP scare is about extracting $$ from Congress.

    I admire your work on the aircraft harnesses.

    I designed them. Commercial, and military. Military and commercial ground eqpt. Radios and controls.

    Again – I will agree that with commercial eqpt. there may be a problem. It will be small.

    In fact the worst design I had with respect to EMP was a ground radio with 1,000 feet of control cable. Just to be sure of zero EMP damage from a close in strike that cable needed 7 shields. But that was a cable out in the open designed to take a nuke a couple of miles away. With every aspect of the problem worst case – some shields not properly bonded, cable in the worst orientation, etc.

    BTW we bought the cable off the shelf. The job was typical military gold plating. Five shields would probably been more than enough. But, you could buy the stuff off the shelf and it was considered good by design. At least it was one less thing we had to justify in the RFP response. Ultimately everything got tested.

  23. M. Simon:

    From your mouth to G*d’s ears…

    Seriously, I greatly respect your arguments, but I read an awful lot on the other side of the fence that disagrees with you.

    So for now, I take it seriously. I have posted many times on many topics – Honor the Threat.




  25. 13. You find your caps lock key. Please!

    14. All possible guilty parties are provided with a border-to-border glass carpet, courtesy of the US.

    Gotta remember that, while the US civilian infrastructure is one thing, the military infrastructure is something else altogether; it’s hardened to survive, at least in part, a maximum-saturation bombardment from the Soviets. The idea that a single EMP device would materially degrade the US’s immediate counter-strike ability is pure fantasy. (Of course, that doesn’t even take into account all the nuclear missile subs…)

    Also a fantasy is the idea that the US would sustain a nuclear attack and fail to respond just because the guilty party was unclear. Not bloody likely!

  26. My two cents is on M. Simon’s side of the debate for whatever that’s worth. Less of a threat than predicted. Anything not directly connected to an antenna will probably do better than the doomsayers predict.

    As for communications infrastructure. Cell phones are toast, I suspect the cell companies will have to more or less replace e every single tower in the area of effect. Wireless networks, toast. Phones, toast. A lot of fried cable modems, dsl modems, etc. The key fiber optic data networks are, well, fiber optic and so won’t function as antennas, so I suspect the switching stations will do better than average, and they’re plug and play installations essentially anyway. Figure key US based backbone routes being down for a day or two, forcing traffic rerouting around outages (which will cause overloading and some traffic related outages along other routes).

    Data loss should be ultimately negligible. Anything important should be backed up regularly (you do back up YOUR important information, right?). Optical backup media is immune to EMP, and the magnetic storage material (tape) favored by corps is routinely stored in fireproof safes which should also function as workable faraday cages and should ride out the blast just fine.

    Plenty of scrambled in-progress and same day transactions, and I’m sure lots of entertaining customer service stories (at least once the phones come back on…), but the ‘no one knows who owns what’ scenario just isn’t in the cards.

    The biggest problem is probably going to be the most mundane, simply replacing the legions of fried office computers, servers, and industrial controllers. There are only a few of them and you can’t build new ones in time frames less than 18 months (maybe a year if you really pushed it). It might end up taking months to really replace everything.

    If I thought an attack was a serious possibility, I’d buy stock in the Taiwanese semi-conductor plants, Dell, HP, and Cisco. They’ll be essentially manufacturing money. They also will serve nicely as the required white industrialist villains for the Hollywood adaptation.

  27. Doh, editing error.

    That second to last paragraph should read…

    The biggest problem is probably going to be the most mundane, simply replacing the legions of fried office computers, servers, and industrial controllers. The problem is semiconductor manufacturing plants. There are only a few of them and you can’t build new ones in time frames less than 18 months (maybe a year if you really pushed it). It might end up taking months to really replace everything.

  28. _”Also a fantasy is the idea that the US would sustain a nuclear attack and fail to respond just because the guilty party was unclear. Not bloody likely!”_

    I’m not so sure about that. Lets say a nuke goes off in New York Harbor in 10 minutes- who does President Obama nuke in return?

  29. Mark, let’s be reasonable here. Obama isn’t likely to nuke someone within the hour. But they’ll know pretty quickly (just by measuring the type of particles in the blast which are specific to mines, and processors).

    Subs will probably be in position next to the likely suspects pretty quickly.

  30. _”Mark, let’s be reasonable here. Obama isn’t likely to nuke someone within the hour.”_

    Therein lies the problem. It would be weeks if not longer (if ever) before a ‘smoking gun’ could be determined. With the entire world begging the president not to punish the innocent population of Tehran, do you still see Obama pushing the button? What if Russia or China threatened to reply in the interim? Would it be worth risking Armageddon to ‘get back’ at NK or Iran?

    I just don’t buy it. MAD is based on instant reciprocity. Just the _thought_ that one side can get in a free shot and potentially decline decide against reprisal upsets that apple cart.

    Our best defense is to announce a doctrine of instant nuclear assault on ALL rogue regimes in the event of a nuclear attack. THAT would provide a massive incentive not to be the 2nd craziest kid on the block.

  31. I did two old posts at Armed Liberal on this…unfortunately, the site isn’t up. Let me go review them and see if they are worth reposting…


  32. bq. Lets say a nuke goes off in New York Harbor in 10 minutes- who does President Obama nuke in return?

    Where’s Dick Cheney at the moment?

  33. 1) I think it’s easier to gather evidence (& respond) than you think it is.

    2)I don’t think it really matters if it’s a an hour or a day, or even a week. Knowing that your country is about to become radioactive glass is not just a pithy threat. No nation will attempt to attack us so brazenly. And the military has 40 years of preparation on how to respond, spanning (at least) half a dozen different administrations.

  34. To #39 number 2

    “Knowing that your country is about to become radioactive glass is not just a pithy threat. No nation will attempt to attack us so brazenly.”

    That seems like a comforting and farfetched assumption. Something that springs to mind is that the masterminds behind a possible attack would be in a safe remote location like the Caymans and wouldn’t hesistate to attack, knowing they were safely cubbyholed away from the ensuing fray and US counterattack. Some of these men might see their own country’s destruction as a loss on the way to victory in a larger sense. I have no evidence to back up this theory other than observing the deeply ingrained suicidal behavior displayed by the seedier segments of Islamic culture. Why not suicide of a culture on the way to greater “achievement”?

  35. Lets say a nuke goes off in New York Harbor in 10 minutes- who does President Obama nuke in return?

    If that happens, we are going to make it very clear to Iran that they are going to have to decide whether they want to come to the barbecue or not.

  36. _”1) I think it’s easier to gather evidence (& respond) than you think it is.”_

    I think outside of 007 movies, this kind of evidence takes time to obtain, process, and verify, and is often inconclusive outside of laboratory perfection. Not to mention it is being examined by the same people that brought us our Iraq WMD intel. Its not enough to be sure- you have to be able to provide evidence that is self-evident to others.

    _”2)I don’t think it really matters if it’s a an hour or a day, or even a week. Knowing that your country is about to become radioactive glass is not just a pithy threat. No nation will attempt to attack us so brazenly. And the military has 40 years of preparation on how to respond, spanning (at least) half a dozen different administrations.”_

    If thats the case, why are we so worked up about NK and Iran to begin with? And I think the real issue is what happens if a 3rd party is given or gets ahold of these weapons.

    Take now, for instance. If there were a million protesters in Tehran opposing the government, and we had pretty good indication that a rogue nuke had originated in Iran, would we still nuke Tehran? I have serious doubts about that, and I think its a lot easier to bluster about it in theory than to be the guy who makes that decision.

  37. 1)It took them only hours to identify bin Laden’s involvement after 9/11? I’m also curious, how easily can we spot rockets and satellites in low orbit coming into US airspace? (Assuming we’re still talking EMP here).

    2)_If thats the case, why are we so worked up about NK and Iran to begin with?_

    Better safe than sorry. It’s also not (completely) about us either. It’s about neighboring countries, south korea, Iraq, (Israel). It’s about preventing ‘nuclear neighbors’ who threaten and create instability. And of course, about exporting nukes to terrorist groups.

    Of course, this post is about EMP blasts. Terrorist groups may have the power to smuggle in a nuke, but they do not have the power to send and EMP to the orbit AL discusses.

  38. _”It took them only hours to identify bin Laden’s involvement after 9/11?”_

    Well it helped that he claimed credit. I think this case would be more of a technological exercise to identify specific radiation signatures than a political game of who dun it.

    _”I’m also curious, how easily can we spot rockets and satellites in low orbit coming into US airspace?”_

    Easily. But if the rocket was launched from a freighter that is immediately scuttled… The scenario in question isn’t about an ICBM launched from NK- obviously we’d be on top of that before it ever left the ground. This is more about a rogue nuke with no calling card, EMP or conventional. In that case I don’t think you could count on a return address in minutes or hours. Certainly you could make a firm guess, but nothing that you could, say, take to the UN without looking like a fool.

  39. _It took them only hours to identify bin Laden’s involvement after 9/11?_

    Personally, I was thinking that September that Bin Laden hadn’t done anything big during the summer…

    _I’m also curious, how easily can we spot rockets and satellites in low orbit coming into US airspace? (Assuming we’re still talking EMP here)_

    It is not a secret that the USAF built already in the 1960’s a radar network and associated computers to track all objects in orbit. Otherwise, it would be too easy to place a disguished nuke in orbit (although violating a treaty between the superpowers) and years later make it fall into a major city.

    And, I ask myself, wouldn’t something like that be already implemented for ships? After the “Prestige Oil Spill”:http://en.wikipedia.org/wiki/Prestige_oil_spill, (don’t take the link too seriously, no mention to the loose ends in Moscow and London) it was much talked on how no ship enters the 200 mile limit around the States without all the papers OK, begining from sanitary inspection and ending with the charts up-to-date…

    To launch a medium range missile from a ship against the U.S.? It is not as easy as it seems.

    By the way, although being true that an EMP releases locally the same amount of energy compared to a lightning stroke, the forward flank of that releasing is steeper, constituing a harder environment.

  40. Harsher environment, I meant.

    Furthermore, high altitude EMP radiation is richer in higher frequencies, that have increased penetrability.

    On the other hand, varistors and zeners seem to give at least some kind of protection for military equipment.

    There are other effects, but I don’t think HEMP would affect modern equipment – beyond the grid – so much. It would constitute the end of civilization only for the country which dared.

  41. Einstein obviously hasn’t bothered to read the post; light planes don’t fly 15 miles up and the damage from a nuke at 10,000 feet would be as much about blast effect as about EMP.


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