Effects of an EMP

MDSchafer

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So, I'm starting to conceptualize another work about what happens to a floor of nurses when after an EMP blast hits a major country. I've been trying to figure out what exactly an EMP does and doesn't do. So, a whole bunch of questions.

Is there a rough year limit for what vehicles would function? Is it like anything from the mid 80's or 1960s? Or is there a more specific time. Also, I've read where the amount of metal in a car might shield a car's electronics from an EMP? Like would it be possible that a lot of newer cars would fail, but the ambulances, being bigger and considerably more metal might survive? Right? The idea I'm working under is that some modern cars would work and some wouldn't.

Phones? I'm assuming all smart phones would be bricked and while old mechanical land lines would still work the infrastructure would be destroyed.

Nuclear power plants? Are they hardened enough to survive a blast? If not, is there some sort of manual backup to make sure the core doesn't cook off?

Burns? Assuming it's a powerful enough EMP to blanket a significant area would people touching metal be burnt by the heat? Also, would the heat be enough to cook cars? Also, would your average light bulb blow up?

How deep underground do you have to be to get some coverage? In pretty much every major hospital there are non-public basements, some of those house generators. Would that be deep enough that the generators would survive? Also, if they weren't turned on at the time, would that effect their survival? Also, what about basic wiring? Assuming the generator worked would outlets have power?

Radios would be hit and miss, right? Also, say you ran to a walmart and snatched up every walkie talkie you could get, a mass number of them would work, right?

Would "The Cloud" survive?
 
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Frankie007

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watch Dark Angel (Jessica Alba). it was based in Seattle after an EMP hit the west coast in 2013. the show is set in 2019/2020.
 

lizmonster

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The first thing you'll want to do is clarify what kind of EMP you're talking about. Is this a natural disaster, or a weapon? If a weapon, it's worth noting that it's not that high-tech to shield something from an EMP, although it'd be expensive/unwieldy to cover (for example) a whole city. I'd expect a nuke plant to be shielded, though, and I'm not sure the age of a car is what's going to protect it (or not) from the voltage surge.

As a general rule, EMPs aren't the shut-it-all-down deus-ex-machina they're used for in a lot of literature, so you'll want to be very specific about both the cause and the effect in your story.
 

MDSchafer

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As a general rule, EMPs aren't the shut-it-all-down deus-ex-machina they're used for in a lot of literature, so you'll want to be very specific about both the cause and the effect in your story.

Actually, I'm planning on drilling down the focus as narrow as I can to what I know, medical and character. The way I'm envisioning it my characters never learn what caused the EMP, or even if it officially is an EMP, but I'm working under the assumption that TV and internet connected devices won't survive for the most part. Also, won't most broadcast equipment go down too? Like television studios wouldn't survive a massive EMP.
 

amergina

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If you use the magic of Google, you might discover that yes, some vehicles will still run, depending on multiple factors, but how long they run will depend on how much fuel they have, since getting fuel might (will) become tricky.
 

lizmonster

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Actually, I'm planning on drilling down the focus as narrow as I can to what I know, medical and character. The way I'm envisioning it my characters never learn what caused the EMP, or even if it officially is an EMP, but I'm working under the assumption that TV and internet connected devices won't survive for the most part. Also, won't most broadcast equipment go down too? Like television studios wouldn't survive a massive EMP.

Like I said, what survives depends on a lot of factors. EMPs don't destroy electronics out of hand, they cause a voltage surge. This can be very destructive, yes; but they're not that difficult to insulate against. (Fighter jets, for example, are apparently armored against EMPs.) Some electronics can survive a voltage surge. Others can be damaged, but reparable. And it also depends on whether or not a particular device is turned on (like your car), or plugged into the wall.

You can probably make this work if you've got a big enough source for your EMP, but you need to understand (whether or not you put it in your text) what the surge is caused by, and do your research on that. Saying "broadcast equipment will go down" isn't meaningful in this context; you need to understand how it might be damaged, and how difficult it would be to fix.

Here's a link with some information I haven't validated elsewhere, but it fits, more or less, with my understanding of EMPs. The short answer is that an EMP, even a powerful one, can certainly be catastrophic, but it's not a big off-switch.

(I had to rewrite an entire subplot of an MS because I was making the big off-switch assumption, so I've been here before. :))
 

Jan74

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Depending on the hospital and equipment affected a floor nurse would be left going back to the basics. IV pumps are mini computers if they are shut down fluids could be given by gravity by calculating the drip factor, ok for basic fluids such as normal saline but trickier if you are running multiple meds over longer periods of time. Vitals could be taken manually such as pulse, resps, and BP, but the o2 sat is by machine. The more complex the care the harder it would be to run the ward. ICU, dialysis, chemo, PICU, OR, ER all of those wards use high tech machinery. At our hospital all the labs, orders, requisitions and charting is done via computer. Some hospitals have machines that dispense medications for the nurses those would be affected also. I would imagine if all computer activity is shut down it would cripple most hospitals.
 

MDSchafer

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Depending on the hospital and equipment affected a floor nurse would be left going back to the basics. IV pumps are mini computers if they are shut down fluids could be given by gravity by calculating the drip factor, ok for basic fluids such as normal saline but trickier if you are running multiple meds over longer periods of time. Vitals could be taken manually such as pulse, resps, and BP, but the o2 sat is by machine. The more complex the care the harder it would be to run the ward. ICU, dialysis, chemo, PICU, OR, ER all of those wards use high tech machinery. At our hospital all the labs, orders, requisitions and charting is done via computer. Some hospitals have machines that dispense medications for the nurses those would be affected also. I would imagine if all computer activity is shut down it would cripple most hospitals.

Yeah, the germ of this idea was when we lost power and had a minute or two before the generator kicked in, or at least it felt that way. At the time one my patients was intubated on fentanyl and propofol drip. The machines are all on batteries, but a EMP blast is a scary thought.

O2 wouldn't be an issue. I carry a pocket pulseox. As I understand it's too small to be effected by an EMP, so there's that.
 

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An EMP essentially short-circuits most electronics. Some things will survive, and other thing will need to be repaired, but wireless communication will certainly be down for awhile. It really depends on how strong the blast is. There was a massive solar flare that engulfed the earth in 1859 called The Carrington Event. The electromagnetic storm affected electronics worldwide. People were being shocked by their telegraphs when they weren't even plugged in, and there were bright, blood-red auroras that lit up the sky. Here's a good source on what would probably happen if a similar event struck earth today. It's a pretty interesting article.

http://news.nationalgeographic.com/...storms-earth-danger-carrington-event-science/
 

Dennis E. Taylor

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Electricity is generated when a wire moves through a magnetic field. That's how generators work. A coil of wires is spun inside a magnetic field formed from some permanent magnets surrounding the coil. Electricity can also be generated by an expanding magnetic field moving across a stationary wire. That's how EMPs work. The stronger the magnetic field and the sharper the pulse (shorter wavelength), the higher the voltage and current generated. The thinner the wire, the more that current will heat the wire. Wires can melt, especially the thin circuit traces on most electronics.

The pulse will also create a voltage proportional to the strength of the magnetic field. Most electronic components these days work at an internal voltage of 5v, IIRC. An EMP can create an instantaneous voltage in the thousands of volts. This is a Bad Thing, and electronic components tend to disappear in little puffs of smoke when that happens.

Old vehicles tend to survive EMPs better because A) they don't have any of that consarned newfangled electronical crap, dagnabit, and B) the wiring tends to be large and robust, able to handle a momentary surge.

You can protect against EMPs by putting a shield around your electronics, which just consists of either a grounded metal shell or a wire mesh. Of course, the stronger the EMP, the better the shielding has to be.
 

Mark HJ

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The outcome of an EMP is going to be very variable. We had a 'baby emp' (aka lightning strike) a few years back. I don't know exactly how close it hit, but various bits of household electronics died, regardless of whether they were plugged in. So, the router died, but then the overhead phone lines picked up a serious hit. Pretty much everyone here lost their phones, but whilst our neighbour lost the phone itself, ours survived and only the master socket for the house got fried.

My PC survived but my partner's (three feet away) died - both were turned off, and both are isolated from mains spikes by a UPS which was also turned off, so this was just the pulse kicking off voltage surges in the cabling. My partner's fancy phone, 1 foot up from the PC, survived. The printer, two feet to the left, died. The hot air gun we use to light the stove experienced internal arcing (which is very spooky, standing in the dark because the sub-station went out, and seeing blue sparks by the hearth) but still works, albeit with some odd noises from the fan. Amazingly, both the TV and PVR survived, even though both were still connected to the out-door antenna.

In terms of 'proper' EMPs, that was something small, but my little physicists brain says the intensity of the pulse drops off as the square of the distance from source, so unless you have a truly massive overhead EMP, you will see far more things surviving, and more variation over what survives the further you get from the epi-centre.