EMP, Why bother?

[Bunsen]

(Just for clarification purposes I was talking about a nuclear weapon being detonated in the atmosphere, so wouldn't the Gamma Rays hit the electrical device in question just like how I was saying since you said that the illustration was correct???)

That illustration shows the case for a weapon detonated in space (or the far upper atmosphere), which is the only way to produce a widespread EMP. Anyone down here on the ground is separated from the blast by several miles of air, which will completely block the gamma rays. As for the part about plugged/unplugged, household wiring can act as an antenna to pick up the burst of radio waves and damage things connected to it. Unplugging devices reduces their vulnerability, maybe by a large margin depending on the device.

Weapons detonated at low altitude (i.e. in the lower atmosphere) don't produce a widespread EMP. If they're detonated close enough to the surface, then there's a "source region EMP" created in the vicinity of the burst (in the region where the gamma rays are getting absorbed), but that's only strong enough to matter at rather short ranges. If you're close enough to get your cell phone fried by that, it won't matter very much because your scorched, irradiated, pulverized corpse isn't going to be making many calls anyway. SREMP matters if you're designing a missile silo's electrical and communication systems, but not for much else.

[Browning 35]

(Just for clarification purposes I was talking about a nuclear weapon being detonated in the atmosphere, so wouldn't the Gamma Rays hit the electrical device in question just like how I was saying since you said that the illustration was correct???)

That illustration shows the case for a weapon detonated in space (or the far upper atmosphere), which is the only way to produce a widespread EMP. Anyone down here on the ground is separated from the blast by several miles of air, which will completely block the gamma rays. As for the part about plugged/unplugged, household wiring can act as an antenna to pick up the burst of radio waves and damage things connected to it. Unplugging devices reduces their vulnerability, maybe by a large margin depending on the device.

Weapons detonated at low altitude (i.e. in the lower atmosphere) don't produce a widespread EMP. If they're detonated close enough to the surface, then there's a "source region EMP" created in the vicinity of the burst (in the region where the gamma rays are getting absorbed), but that's only strong enough to matter at rather short ranges. If you're close enough to get your cell phone fried by that, it won't matter very much because your scorched, irradiated, pulverized corpse isn't going to be making many calls anyway. SREMP matters if you're designing a missile silo's electrical and communication systems, but not for much else.

Okay, then we were saying the same exact thing.

A nuclear detonation at ground level would produce some EMP that would be experienced by people a ways away from the blast and some of their electronics might not work, but it would hardly be an 'asymmetrical strike' (I'm pretty sure that would be considered a full on strike).

Even if I was 100 miles away I'd be more worried about radioactive fallout than my toaster not working. =)

[s2la]

I've been following this thread for a while now, and finally couldn't let this nonsense go unanswered.

First, most of what has been said in this thread is effectively the output of the south end of a north-bound bull. At least one of you claims to be an expert, yetmdoesn't know what in the hell he's talking about, and when presented with the evidence and a formal national academies report, has the balls to say that it agrees with his head-in-the sand opinion.

Second, there are several posts saying "why bother?" EMPs will come from nukes, and nukes aren't survivable. mzmadmike posted the Carrington event as an example of why one should bother preparing for an EMP. Of course he got attacked saying that CMEs are not EMPS and can't do the damage of an EMP. Wrong, again. A flare or CME *especially* during a solar minimum, would wipe out most if not all of the world's electrical infrastructure. It wouldn't matter if your car ran if there's no way to get gasoline, or if your laptop worked with no internet.

Third, the idea that a device has to have an antenna to be affected by EMP is crap. If that is true, why is everyone so worried about electronics? Does a laptop CPU *really* have a long antenna? No.

Fourth, you are all arguing semantics over whether a nuke or flare strong enough to fry electronics won't just fry *you* - therefore it's not worth preparing for. Again, bull crap.

Get your collective heads out of Wikipedia - which is 1/2 truth, 1/2 lies, and 1/2 the kind of uninformed guesswork that this thread has been perpetuating - and go read the primary sources. They are available on the internet if you go looking for them. If you don't understand them, find someone who *does*! Stop guessing and mutually stroking each other when someone posts something you like!

Now, the facts, from someone that knows and works with physics and electronics every day and has to deal with the consequences of EM interference, pulses and induced currents...

EMPs have 3 parts - E1, E2, E3.

E1 is the effect caused by gamma rays striking atmospheric molecules and releasing electrons. This is the nuke-derived *pulse*, and it will fry unprotected electronics.

E2 is the static electric discharge conducted through the air to grounded conductors.

E3 is the geomagnetic pulse and can come from a nuke or solar event. Flares, CMEs and nukes *push* against the Earth's magnetic field and the resulting wave and rebound induces a current in long conductors.

Antennas: Antennas are important in all three phases: they can be affected by the electron pulse, ground the static discharge, or received an induced current. Grounding the antenna prior to the electronics will protect against E2, but not E3. An antenna is not really affected by E1 - nor is lack of an antenna protection against E1.

Lack of antenna protecting electronics: Bullcrap. The electron shower from the gamma ray pulse affects all electrical conductors. The ones that develop more heat than they can dissipate will melt. In common terms that means long wires and antennas develop large currents, but the microns thick wiring in silicon chips can *not* dissipate more than a few calories worth of heat, so they melt. The key is not *length* of the conductor, but a combination of length, thickness, and the melting point of the conductor.

Faraday cages: (1) Faraday cages *must* be grounded, and they must be made of a good conductor with holes no larger than the wavelength of the radiation in the pulse. (2) Faraday cages don't protect against E3, and their E2 protection is only as good as the ground conductor. In practical terms an effective faraday cage can be made from mesh with holes no larger than 1/2 centimeter and block all radio and microwave radiation. Cars are not good faraday cages - that huge windshield is not exactly <1/2 centimeter. Aluminum is okay for faraday cages, but foil is not very effective - the conductor is too *thin*. Steel and copper *wire* mesh are better. There is a reason why commercial shielding and grounding uses braided wire and mesh for shielding and again, to be effective, a Faraday cage must be *grounded*.

Nukes and EMP: It's true that the nuke needs to be above the densest part of the atmosphere. About 100 miles will do. EMP is not strictly line of sight, it follows the Earth's magnetic force lines. Guess what - North America is a hell of a lot more susceptible to EMP than anywhere else- mostly because of the magnetic field emanating from the magenetic North Pole (which, duh, is in North America). So a 100 kt nuke over Canada can EMP a large portion of the US. Sorry, guys, but that's a scenario in which EMP is a very real threat *without* nuclear war.

CMEs, Solar flares and EMP: A solar flare or corona mass ejection (CME) releases high energy particles at 0.25-1.0% light speed. Astronomers will see the flare/CME, and the effects will show up around 800 hrs later. The impact of these particles with the Earths magnetosphere will (1) *push* against the geomagnetic field [E3], and (2) release additional gamma rays in the extreme upper atmosphere, resulting in *some* gammas making their way to the lower atmosphere to cause E1 - just not as severe as a nuke. The E3, however, will be severe, as in the 1859 Carrington Event. And it's not just long power cables that will be affected! *Any* long conductors will be charged. The power lines from generating plant to transformer may be protected, but what about the *plumbing*? There are also geological features that carry charges, the North American high plains are full of them - also nickel, iron, bauxite, gold, silver veins and deposits! The geomagnetic pulse may be relatively slow from an EM standpoint (effectively DC, someone said) but it is nonetheless an electrical charge, and it is *not* the instantaneous pulse, but the capacitive charging and discharging that produces the oscillation that results in damaging voltage. Most electronic devices such as diodes and transistors conduct current only in one direction and block flow in the opposite direction, but each also has a failure point - supply enough charge and they fail and conduct in both directions - a short circuit. The key is charge density, and the specific failure is dependent on how much charge, and how much conductor, be it 12 micron traces in your laptop or inch-thick 440 V power lines.

So. Here's the facts. Do what you wish with the knowledge, but at least stop standing around in a circle stroking each other with conjecture and half-truths.

[KC44]

I've been following this thread for a while now, and finally couldn't let this nonsense go unanswered.

Welcome to the forum. Swing by the Intro section and say Howdy.

KC

[WhoShotJR]

CMEs, Solar flares and EMP: A solar flare or corona mass ejection (CME) releases high energy particles at 0.25-1.0% light speed. Astronomers will see the flare/CME, and the effects will show up around 800 hrs later.

Not nitpick, but wouldn't that be 800 minutes?

[mzmadmike]

186,000 MPS.

93 million miles to Earth.

500 seconds, or 8 min, 20 seconds.

1% = 50,000 seconds, 833 minutes

13.8 hours

So, yes, minutes.

[Tater Raider]

http://www.globalsecurity.org/military/systems/munitions/hpm.htm#

If one country has this device then it is a fair bet that other countries are capable of manufacturing it.

You do your preps and I'll do mine.

I'm done with this discussion. Too many people participating are afraid to say they do not know something. Too many others are tearing people down for prepping themselves for a percieved threat. That's like tearing someone down for preparing for a zombie outbreak.

Wait a minute...



The question was, "Why prep for an EMP?" Those who consider EMP something to prep for have answered and been ridiculed for it. Those of you doing the mocking should be ashamed (car = Faraday Cage comes to mind).

[mzmadmike]

"Explosive Flux Compression Generator."

Basically a giant alternator with a shaped charge core. Explosion causes a short circuit. 1950s experiments generated millions of gauss and millions of amps. Modern ones are undoubtedly faster (meaning harder on circuitry) and stronger.

Incidentally, nukes are not the be all and end all, regardless of badly-researched, apocalyptic drool from the 1970s (I know something professionally about science and science fiction ). I live 18 miles from downtown Indy. If terrorists set off a 20kT nuke in Monument Circle, my main concern would be mobs of fleeing people, not fallout or blast.

At the peak of the Cold War, every nuke in existence, if detonated for maximum effect, would be about enough to glaze Texas. Go look at Texas on a world map. The fallout would increase cancer rates downwind, to varying degrees. However, seeing as there are people who survived both Hiroshima and Nagasaki and died of natural causes within the last year, and people visiting and working at Ground Zero in both cities, you can deduce it's not as bad as the above mentioned pop-fiction made it out to be. Nuclear Winter was debunked by 1980--seems the people proposing it simultaneously assumed ground bursts for maximum dust and airbursts for maximum firestorm. This also assumes EVERY bomb gets launched and successfully detonates. So they were off by several orders of magnitude over reality.

Terrorists with a nuke? Doesn't scare me. Terrorists with a couple of flux bombs in NYC and Chicago? Well, I don't live there, so no skin off my nose.

[WhoShotJR]

Terrorists with a nuke? Doesn't scare me. Terrorists with a couple of flux bombs in NYC and Chicago? Well, I don't live there, so no skin off my nose.

I think you may be ignoring the social, political, and economic effect on the US, and as a result the industrialized world, such attacks would cause.

[mzmadmike]

Nope. Those do scare me.

The nukes themselves do not.

Keep in mind that large chunks of the Earth would never notice if the power went out.

Europe and North America are SOL.

[MikeDoyle]

IIRC, the largish chunks that wouldn't notice the power going out have very low population densities. If the lights go out and stay out in Europe and North America, that implies that secondary effects are going to yield a pretty large and very nasty population adjustment - my gut's telling me to take 50% casualties within 6-12 months from secondary effects as a floor figure, but I don't have relevant expertise to hold an informed opinion. Comments?

[WhoShotJR]

IIRC, the largish chunks that wouldn't notice the power going out have very low population densities. If the lights go out and stay out in Europe and North America, that implies that secondary effects are going to yield a pretty large and very nasty population adjustment - my gut's telling me to take 50% casualties within 6-12 months from secondary effects as a floor figure, but I don't have relevant expertise to hold an informed opinion. Comments?

There are no experts who can answer such a question. Maybe people who can convince you they have an answer, but there are just too many variables. The dynamic which would play out between the top (gov, mil) and the bottom (rich or poor wouldn't matter, it's level of preparation) no one can predict. They can attempt to predict based on historical precedent, but who the hell really knows. If we ever had a truly lights out situation, I'd guess 30-75% population die off, especially in highly urbanized areas.

[MikeDoyle]

Yeah, probably so - I'd lean towards the high side of that range you gave, b/c a) larger starting population competing for resources, and b) atrophy of our aggregate low-tech skillsets after being two or three generations away from a level where we'd actually have need to practice them.

On a personal note, I'm in a middlin' population center the I-64 corridor between two largeish population centers. As matters stand, IMHO, if a major EMP event occurs with those secondary effects, I figure I'm pretty much hosed. Minor event, not so much (barring mass hysteria, of course).

[mzmadmike]

95% in North America. It doesn't take a lot of math to figure out.

Probably the same in Europe.

Africa and rural Asia are NOT low density, and they'd not notice. They'd be our future.

[MikeDoyle]

I stand corrected on Asia and Africa - but that also goes to my point about skill atrophy. They've had more practice at subsistence-level than we have up here, which implies we'd be hit harder by a catastrophic failure (BTW [ETA: "and off-topic"], not to suck up, Mike, but you wrote something along those lines that I read a little bit ago... good stuff)

The bottom line still stands: in a major event, people in EU/NA are hosed. I didn't quite expect 95% - I'm guessing synergistic effects, like no power grid --> no oil production --> no fuel + no petrochemicals (e.g., plastics, fertilizers, etc)

[Rev]

A lot of Asian countries are screwed. They ship in a lot of food. Really the problem with third world countries is that they depend on a lot of foreign aid and they'd be hit frightfully hard by the political and economic breakdown. Added on top of that they often don't have the technological capability to repair a lot of their infrastructure and plants and it starts painting a dire picture, but perhaps not quite as bad as us in America. I see warfare on a level so far unseen on every level, tribal, regional, and continental. Yes I know warfare is pretty common in Africa, but it’s normally on a small tribal level. If you pay attention war between nation states isn’t that common. Mostly because we don’t allow that shite, it interferes with commerce. Not to mention it puts an end to all this aid warlords and corrupt politicians use to line their pockets. So what I’m getting at, bushmen in Africa probably unaffected. People in population centers? Starvation, disease, and probably being caught in the crossfire. Really just about what they got going on now, but at a more intense level. South America I think has the best chance to pull through an EMP and the crash of the world economy if they can keep their government together.

[mzmadmike]

If there is no power to pump water and no working cars (Worst case), what happens to everyone in the Southwest, Mexican desert and High Arctic?

They die. The end.

Big cities have about 8 HOURS of food on hand: They die in fires, rape, robbery, rioting. The end.

Mid sized cities? Three days of food on hand. Then they spread across the countryside, and anyone with any skill kills every edible animal (all of them), and eats all the crops for this year. There won't be any next year. Everyone starves. The end.

The continent can support a sizable non-industrial population, but it takes time to change from industrial to non-industrial. Without time, everyone dies. The end.

Fortunately, a worst case scenario is very unlikely.

The pre-mass industrial population of this continent was about 100 million, and analyses of land use and resources support that as quite doable. However, 400 million people on this continent mean an IMMEDIATE 3:1 excess of feedable mouths. Unless the 3 graciously lie down and die politely, the 1 won't have enough food to live long enough convert back to a non-industrial culture. Then they won't have enough manpower and people with knowledge of mechanical tools. Then they won't have the means to acquire raw materials and forge/form them.

Then the very few smart, stubborn and sociopathic enough to hang onto their resources while everyone around them dies will GRADUALLY build it back up.

By which time hordes of people better prepared for that kind of lifestyle will have swarmed up into North America from Central and South America, and into Europe from Central Asia.

The good news is the peak of the probability curve is about 350 years from now, and we hopefully will have a much more durable technology before then.

Of course, the estimates may also be wrong, and it may happen in 10,000 years. Or tomorrow. We've only had any reason to notice CMEs for 150 years.

[s2la]

BIll Forstchen's book "One Second After" posed one aspect of the *survival* that few really think of. mzmadmike mentioned that the pre-industrial carrying capacity of this *continent* is 100 million, and we currently have over 400 million - however, that is a mean over the entire N. Am continent.

Forstchen's point was that just because one *can* live off of hunting the local game... doesn't mean there will be any game to hunt when your 1 million neighbors from the metro area next door try to live off of that game too.

Other points are that a nuke war scenario is quite likely survivable. After that? How well prepared are you? *That's* the answer to "Why bother?"

[WhoShotJR]

[quote="s2la"
Forstchen's point was that just because one *can* live off of hunting the local game... doesn't mean there will be any game to hunt when your 1 million neighbors from the metro area next door try to live off of that game too.

Other points are that a nuke war scenario is quite likely survivable. After that? How well prepared are you? *That's* the answer to "Why bother?"[/quote]


The Great Depression was hardly a PAW type event, yet by 1940 the native deer population in GA was essentially zero. This during a really bad economic situation, not a FUBAR situation.

[mzmadmike]

The Great Depression was hardly a PAW type event, yet by 1940 the native deer population in GA was essentially zero. This during a really bad economic situation, not a FUBAR situation.

And GA was a lot less populous then, and GA is NOT very high in population density now, though considerably higher.

[calearner]

This article:

http://www.wired.co.uk/news/archive/201 ... olar-storm

says we're sync'ing up 2 different solar cycles (the sunspot cycle and the magnetic energy cycle) in 2013 and the last time this cycle sync happened was 1859 which was when the Carrington Event occurred and highly disrupted the Telegraph.

Of course, Browning 35's excellent post links to a NASA article that isn't as worried as Wired UK and possibly has better researchers.

One way to prepare for an EMP event seems to be building a Faraday cage for smaller electronic items.

This article gives a nice DIY approach to that:

http://preparednesspro.wordpress.com/20 ... aday-cage/

Or the turbo-redundancy approach of comment #15 from that article:

"It seems that multiple layers of protection is the recommendation. I will place my items in an ESD Bag. (I have a bunch of them leftover from building and upgrading PCs) Sealed with electrical tape, wrapped in heavy duty Foil and then placed in a Plastic bucket in a grounded metal trash can."

Looks like I need to head over to Home Depot and pick up a galvanized steel trash can to protect my toaster.

[Glennbo]

Some of the responses on this thread sound like the stuff we all hear from non-preppers.

There seems to be an inordinate amount of willful denial on this forum when this subject comes up, as if people just can't wrap their heads around the concept and extrapolate the consequences.

At a wargame tournament last year I had an opportunity to speak to a Colonel involved in weapons technology at the Pentagon about protecting my expensive hand-crank radio (AM, FM, Shortwave) from an EMP attack. He just laughed and told me to bury it thirty feet in the ground.

I told him that was not possible for me and could he please help me with some other reccomendation. I was very persistant because this subject means a lot to me and I finally had the ear of somebody who knew his stuff. EMP is one of the reasons I've stored three months worth of water. He wouldn't give me an answer except to repeat in a very serious manner that I should bury it thirty feet underground, no matter how hard I tried to pry an alternative out of him. It was weird. We were walking back from a Subway together and had plenty of time to discuss it, but he wouldn't elaborate. Either he didn't know (unlikely), or he thought shielding was too impractical for an ordinary person like me to even attempt.

All the encounter did was further unnerve me. He gave the impression that EMP will be worse than people think; that the "why bother" attitude should be directed towards shielding, not general preperation or likelyhood of an event.

I still haven't "bothered" to protect my precious radio because of his pessimism. But I have stored a lot of water and food...and ammo. I've also begun to give more serious attention to acquiring the means to keep warm in the winter.

[mzmadmike]

The Wired article is not very good, to be honest. The sunspot cycles are unlikely to do more than affect radio reception a bit, and produce pretty auroras. Of course, a large prominence or flare will be a bit more noticeable.

There are other cycles, too, and the 22 year is just a harmonic of the 11 year one.

[DropZedFred]

I work with over 1,000 RF products as a support engineer. We have 5 faraday cages on site, ranging from what you would expect one to look like (copper cage) all the way up to a full blown military style RF "Clean Room". I can tell you from my testing that most shielding attemps will fail. The copper room is all but useless in blocking anything but outside lighting noise, and some external RF, but stong sources leak like a pig. The biggest problem being the power is passed through a sheilded connection, not filtered.
Then next one up is a copper lined "walk-in freezer" with RF and noise filters on all the incoming power connection (actual RF filters on each phase of power and ground), it does better, but there are still dozens of RF sources detected.
The "7 figure" RF clean room, as expected, does a VERY good job on everything, but is so shielded it requires its own air handling/climate control!

Also, an "antenna" is ANYTHING that can be used as an antenna - say a power cord, USB cable, keyboard/mouse cable - which can couple the EMP to a piece of electronics. If you store anything, make sure the antenna wire, power cord and associated cabling is stored separately or at least disconnected.

Many commercial faraday bags used for digital forensics are near useless alone - it requires multiple bags, one inside the other (openings at opposite ends!) to keep even weak signals out.

Personally, my EMP preps are for the results: long term loss of power, no water, food distribution interruptions, panic.
Since electric power transformers will be the biggest issue, expect 6mo repairs or longer. We're still working on 3mos food and 2 weeks water...