A brief overview, from the average person’s
perspective
The lights
go out, your computer and cell phone stop working. Most sensitive electronic
devices are destroyed instantly and quietly. A half second later random light
bulbs will pop and there will be sparks from various electronic appliances and
wall outlets. These may start small fires, but most will be harmless. Next
there will be a spooky glow from neon lights (those that did not pop) and
plasma TVs. Meanwhile the power lines will become supercharged over the next
ten seconds, resulting in transformer explosions and some fires. But most
seriously the power generators themselves may be damaged.
Most
vehicles will temporarily malfunction. Those with computers integral to their
functioning will be permanently disabled. Those which are mostly mechanical
with a simple durable electric system should be easy to restart. Many air
planes will crash, because their flight controls are entirely computerized.
Small planes and old planes stand a good chance of making an emergency landing
if they have a fly by wire system.
The details of why these events are likely to
happen in an EMP
There are three components of a nuclear EMP, are called E1, E2 and E3.
The E1 pulse is the very fast component of nuclear EMP. It
is a very brief but intense electromagnetic field that causes electrical
breakdown voltages to be exceeded. E1 is the component that can destroy
computers and communications equipment. Ordinary lightning protectors do not
provide effective protection against it.
The E2 component is generated by scattered gamma rays. It
lasts about one second. The E2 pulse has many similarities to the
electromagnetic pulses produced by lightning. The main potential problem with
the E2 component is the fact that it immediately follows the E1 components,
which will likely damage the devices that would normally protect against
lightning surges.
The E3 pulse is very different from the other two components
of EMP. It is a very slow pulse, lasting tens of seconds, that is caused by the
nuclear detonation heaving the Earth's magnetic field out of the way, followed
by the restoration of the magnetic field to its natural place. The E3 component
has similarities to a geomagnetic storm caused by a very severe solar flare. Like
these storm, E3 can cause geomagnetically induced currents in long electrical
conductors, which can then damage components such as power line transformers.
The well known historic examples
In1962, a 1.44 megaton United States nuclear test in space, 400 km above the mid-Pacific Ocean, called the Starfish Prime test, demonstrated to scientists that the magnitude and effects of a high altitude nuclear explosion were much larger than had been calculated. Starfish Prime caused electrical damage in Hawaii, about 1,445 km away from the detonation point, knocking out some streetlights, setting off numerous burglar alarms and damaging a telephone company microwave tower. This was almost all attributed to the E1 pulse. ( Also the test destroyed several satellites, but this was later found to be because of a lingering radioactive zone, not because of EMP )In 1962, the Soviet Union also performed an EMP-producing nuclear test in space 290 km over Kazakhstan. Although the weapon was much smaller (300 kiloton) than the Starfish Prime test the effects were greater, since the test was done over a populated large land mass. The most dramatic effect was the E3 pulse inducing an electric current surge in a long underground power line that caused a fire in the power plant in the city of Karaganda. As expected the E1 pulse damaged radios up to about 600 km and knocked out radar stations up to 1000 km away. Also the EMP caused a voltage surge in the telephone lines over a 750 km area, causing all the fuses in the line to blow.
Critical importance of later research
The Soviet test bomb was not very big nor was it very good at producing an EMP. If the Starfish bomb had been used in the Kazakhstan test the damage would have been much greater, over an area twice as large.
The modern EMP attack example
If one of the 500 kiloton bombs ( a standard warhead, one of
three, in an ICBM ) detonated 250 km above the central United States,
the economy of the country would be essentially destroyed
instantaneously. Very little of the country's electrical or electronic
infrastructure would still be functional. This is not to say that every device would be destroyed, but the
interdependence of different infrastructures makes it possible to stop nearly
all economic activity with only limited damage to critical
infrastructures. It would likely be months or years before most of the
electrical grid could be repaired.
The instantaneous shutdown of the power grid would occur
because of the widespread use of solid-state SCADAs (supervisory control and
data acquisition devices). These would be destroyed by the E1 pulse, but
could probably be replaced within a few weeks. The greatest problem would
be the loss of many critical large power transformers due to E3 induced currents.
These components are no longer made in America and only a handful are in
reserve nationwide.
Myth-ing EMP facts
In writings on the internet, there is nearly always much confusion about the very different aspects of the various components of nuclear EMP. In addition, there is much confusion over high-altitude nuclear EMP, non-nuclear EMP weapons and solar geomagnetic storms.
Cars dying: Some say that all vehicles traveling will come to a halt, with all modern vehicles damaged because of their use of computerized electronics. Most likely some vehicles will be affected while others are not. Which is actually worse than if all shut down simultaneously; because traffic accidents will be more serious.
Turn equipment off: There is truth to this recommendation. Equipment is more vulnerable if it is operating, because some failure modes involving E1 trigger the system's energy to damage itself. However, damage can also happen, but not as easily, to systems that are turned off.
Since some old technology was EMP-resistant; current tech is also EMP resistant. These myths get things exactly backward. The actual facts are that the main reason that the EMP threat is increasing is the fact that electronic devices are becoming more sensitive to EMP every year.
EMP is not a problem since there are many ways to protect against it. There are many ways to protect against EMP, but they are very rarely being used, especially in the civilian infrastructure. In an effort to save money in the short term, most companies do not even have any effective protection against lightning.
When an EMP hits the ground, the induced electric current heads directly toward the center of the earth. When EMP (or lightning) hits the ground, the currents tend to spread out horizontally. These ground currents can do great damage, especially to underground cables of all kinds. Metal conduits are of little help, and may actually make the situation worse by providing a path for underground currents.
All computer data will be destroyed. Although computer hard drives would not be erased, the electronics in hard drives that are not specifically protected against EMP would probably be destroyed, making it very expensive to recover the data that was still magnetically stored on the hard drive. Also, some of the data would be corrupted on any computer hard drives that were spinning at the time of the EMP attack.
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The EMP event step by step
- A nuclear weapon optimized to produce an EMP, detonated 250 km above Nebraska, would affect the continental United States, southern Canada and northern Mexico.
- The instantaneous E1 pulse will knock out all unprotected communications, including cell phones, radios and even radar equipment, because they are especially good at receiving signals. Other equipment like wireless home networks and solar panels will also be destroyed.
- Any sensitive computerized device is at high risk from the E1 pulse, including implanted medical items like pace makers. The integrated circuits will often overload rendering the device useless, although replacement parts may get it running again. ( Assuming the on-the-shelf parts are not damaged by the EMP )
- Vehicles will fail according to how much they rely on computers and fancy electronics. Their radio systems are certainly doomed. Engines will often go off line, but if they are mostly mechanical they may be repaired with ease. Air craft will lose their computer controlled flight systems, leaving the pilot with no way to fly the plane. Small planes and old one may land safly because they have fly by wire controls. Ships will suffer similar problems, but at lest they are in no immediate danger of sinking.
- Satellites, especially those in low orbit are vulnerable to the E1 pulse. Contrary to popular belief a nuclear EMP will not destroy all satellites in line of sight, because the pulse strength drops off very fast as it moves away from the earth. Many communications satellites, and the GPS network, will survive because they are in high geostationary orbits.
- The E2 pulse will cause damage similar to that of a lightning strike. The more durable electrical systems and appliances will be hit by this wave; some will be damaged others will survive, its hard to predict. Dramatically the E2 pulse will cause many light bulbs to pop and sparks to occur at the ends of electric wires; at well outlets for example. These may start fires, but most will be harmless.
- It is actually the E2 pulse that will temporarily knock out most solid state equipment, like old style engines and appliances.
- The E3 pulse generate overcharge in long wires, power lines and communications lines ( but not in fiber-optic cables ). This will cause transformers and circuit barkers to explode; starting some fires and it may melt some of the lines. Being underground is no guarantee of safety for the lines. Also power generators themselves are at risk. As a side effect the E3 pulse will cause florescent lights and plasma TV screams to glow.
- In the case of large ships, especially passenger liners, which have miles of wiring there is a real danger that the E3 pulse will destroy the ship’s power plant. With luck the simple and durable systems of the life boats will have escaped any serious damage.
- All the above effects will happen in a matter of a few seconds after the EMP is triggered. But what happens next? Many fires will be started by sparks and exploding transformers. Most of these will be easy to get under control, a few will get out of hand because they were not detected quickly. The larger danger comes from the many air planes that will soon be crashing and exploding. The more air traffic your area has, the more danger of a plane crash there is.
- Aside from the immediate destruction of a large air liner crashing into a city, there is the problem of controlling the resulting fire. Many emergency vehicles will be out of action, at lest temporarily. In an optimistic assessment about half the fire trucks and ambulances should be in working order after some simple repairs. The new units with highly computerized systems will be useless. Unfortunately there will be no communications system to co-ordinate emergency efforts, or to report problems.
- Hospitals will be chaotic at best. They will be with out power, until they get their emergency generator running. Although made to kick in directly when main power is lost, most will be damaged to some minor degree by the EMP. If the hospital is lucky, it will have power by the time the flood of people start arriving.
- Traffic accidents will be wide spread. While many vehicles lose power and their drivers try to come to a clean stop, a few will keep going. The first danger is from drivers losing control, with out power-brakes some people will panic. The second danger is from the mobile motorists, who keep going as if they are playing a video game. Some will pull over and stop, but many will try to reach whatever destination they were heading to.
How long to fix the grid?
The problem of spare parts affects more than just the power grid. There has been an overall trend during the past decade toward all commercial enterprises keeping fewer and fewer critical spare parts on hand.
The end of TV ?
Nearly all broadcast stations, especially television stations, would go off the air. Due to the high level of computerized automation, the equipment in most radio and television studios would be so completely destroyed that most commercial stations would be damaged beyond repair. In the current situation, broadcast television transmitters would actually be more easily repairable than studio equipment. With the transition to digital television broadcasting in the United States, the digital encoders would be the extremely weak link in the fragile digital television broadcast chain.
It is likely that a few FM stations could get back on the air within a week of the EMP attack, but they would only be on the air until fuel for their generator ran out, and the electronic starting and control systems of many of the standby generators would be destroyed by the pulse.
A few comments from scientists
As Kyl put it: "Few if any people would die right away. But the loss of power would have a cascading effect on all aspects of U.S. society. Communication would be largely impossible. Lack of refrigeration would leave food rotting in warehouses, exacerbated by a lack of transportation as those vehicles still working simply ran out of gas (which is pumped with electricity). The inability to sanitize and distribute water would quickly threaten public health, not to mention the safety of anyone in the path of the inevitable fires, which would rage unchecked. And as we have seen in areas of natural and other disasters, such circumstances often result in a fairly rapid breakdown of social order."
"American society has grown so dependent on computer
and other electrical systems that we have created our own Achilles' heel of
vulnerability, ironically much greater than those of other, less developed
nations," Abernaky wrote. "When deprived of power, we are in many ways
helpless, as the New York City
blackout made clear. In that case, power was restored quickly because adjacent
areas could provide help. But a large-scale burnout caused by a broad EMP, not
only would there be nobody nearby to help, it could take years to replace destroyed
equipment."
“In addition to the effect on vehicles, we have to consider
the effect on their support structure.” Berman advised “What good does it do if the car will start
if there is no electricity available to run the gas pumps? The really big concern
as far as EMP goes is the grid. Most of the grid is old, has unshielded
transformers, etc. that will be toast if anything of any significance at all
hits. Once the power is out, the JITDS (Just In Time Delivery System) brakes
down, and about three days later, we have a problem. Super markets stop being
super, convenience stores stop being convenient, and in a lot of cases, even
water stops flowing. (Many, if not most, municipal water systems use electric
pumps.) Add to all that; many people get their indoor heating from electric
appliances, (even gas furnaces use electric fans to make them work) if the EMP
hit in winter, well, use your imagination.”
Something to read
A book was released in March 2009
about a fictional EMP attack on the United States. It is
called One Second After by William R. Forstchen, a
best-selling author who has a Ph.D. in military history from Purdue University.
The book covers the period of time from the afternoon of the pulse attack until
exactly one year after the attack.