An Analysis of SitX: Nuclear Blasts

Part I
Most laymen know that the main difference between conventional and nuclear explosions is that most conventional weapons don't inspire their engineers to say that they "have become Death, the destroyer of worlds". In short, nuclear explosions are far more damaging.

In most nuclear weapons that have been studied, approximately 50% of the destruction reigned upon X group comes in the form of blast energy. Another 35% of the damage comes from heat and light, called thermal energy. Finally, and probably one of the most feared byproducts of nuclear explosions, is the radiation, which accounts for approximately 15% of the destruction. This does not take into effect longterm genetic mutations and the like; we're talking simple killing power here. Approximately 67% of that 15% comes from the initial blast (approximately within a minute of the detonation). The remaining 33% or so is released over a period of time (lasting from a few hours to many years).

Most people who've given even barely a nod to the study of nuclear weapons know that such weapons are measured in the amount of energy they release upon detonation. These measurements are then given in the amount of trinitrotoluene (TNT) it would take to release the same amount of energy. For example, a 1-kiloton weapon is one that releases the same amount of energy as 1,000 tons (2,000,000 pounds) of TNT. Energy amounts are typically measured in tons, kilotons, and megatons. A 1-megaton bomb is equivalent to 4.18 x 10^15 joules (4,180,000,000,000,000 joules).

(Source)

In evaluating the destructive power of a weapons system, it is customary to use the concept of equivalent megatons (EMT). Equivalent megatonnage is defined as the actual megatonnage raised to the two-thirds power:

EMT = Y^2/3 where Y is in megatons.

This relation arises from the fact that the destructive power of a bomb does not vary linearly with the yield. The volume the weapon's energy spreads into varies as the cube of the distance, but the destroyed area varies at the square of the distance.

Thus 1 bomb with a yield of 1 megaton would destroy 80 square miles. While 8 bombs, each with a yield of 125 kilotons, would destroy 160 square miles. This relationship is one reason for the development of delivery systems that could carry multiple warheads (MIRVs).

Some terms any researcher on this topic will come across are "ground zero", "surface zero", and/or "hypocenter". All of these generally refer to the same thing, which is the point on Earth immediately above or below the point of detonation. Underground, underwater, and airbone detonations tend to utilize "surface zero" more often than "ground zero".

Another term one may come across is "overpressure". Overpressure refers to the excessive pressure caused by the blast, and is relative to normal air pressure for the region. For example, if you see "50 psi", that means the pressure was 50 pounds per square inch in excess of normal atmospheric pressure. If you see "0.25 psi", it doesn't mean 1/4 of the normal pressure, but rather, if the normal pressure is "1 psi", then "0.25 psi" means the pressure increased to "1.25 psi".

One of the most damaging aspects of a nuclear blast is the change in air pressure, which either crushes objects or knocks them over. Generally speaking, large buildings are destroyed by rapid changes in air pressure, while humans and objects like trees are destroyed by wind.

The damage a nuclear device can cause is augmented by the elevation of the detonation point, though a high-altitude detonation will cause less overpressure at the immediate detonation point than a ground-level detonation. Similarly, a ground-level detonation will cause less overpressure over longer distances.

Information taken from "The Atomic Archive" via Google.

[edit on 31/3/2009 by SolaceMournerVII]

Please let me be stupid for a minute and interject in your finr research. VERY intersting topic to me.

What I wanna do is briefly relate what my Grandad told me about the Bikini Atoll Hydrogen Bomb Test:

BOOM

He said commanding offiers told him to go below, but gave the option to stay on the deck.

Being bored, he went on the deck.

They were told to "put their head between their legs"

He then described something that haunts me to this day.

He told me, "I was scared. It was the most frightful thing I've ever seen. The noise was something you never have heard. It scorched the paint on our ship and we were 5 miles out."

My Navy Papa, then went and got a tattoo of a mushroom cloud on his forearm!

This was DECADES ago.

Part II
Obviously, when a nuclear device is detonated at or near ground level, it effectively "digs" a crater. Some of the material that used to be where the crater is will be deposited at the edge of the crater. Some of it will enter the atmosphere and come back down as radioactive fallout. Immediate fallout is mitigated to a comparably negligible level if the elevation of the detonation point is higher than the circumference of the fireball created by the explosion. Largely, a nuclear blast kills more life by indirect means.

Now we get to that 35%, which is the thermal radiation (read: heat). Generally speaking, thermal radiation travels at the speed of light (just over 670,616,629 miles per hour). The blast wave is traveling a few seconds behind it, so the effects of thermal radiation are seen and felt before the blast is heard (similar to a lightning strike before a thunderclap).

Because of the extreme intensity of the thermal radiation, looking at the explosion will cause "flashblindness", which--if not focused through the lens of the eye thereby causing retinal damage--will be over within a few minutes. Obviously, depending on what an individual is doing while looking at the explosion (i.e., driving a car or flying a plane), serious injury may result due to disorientation and panic caused by flashblindness.

Depending on the explosion, those within a radius of five miles or closer can experience any degree of burn injuries from higher intensities of light. Medically speaking, third-degree burns over 24% of the body or second-degree burns over 30% of the body may prove potentially fatal if left untreated (obviously either case will cause shock). In the United States, facilities exist to treat as many as two thousand burn cases, but a nuclear device can cause as many as five times that amount.

Direct thermal radiation will be intense enough to ignite flammable materials, such as leaves and newspapers. Materials outside of structures will burn quickly and will--again, generally speaking--not be self-sustaining. Thermal radiation that passes through a building will ignite flammable materials that will be of greater concern to individuals further from the hypocenter. Of greater concern will be the damage caused to structures wherein electrical and chemical fires may ignite, causing damage where fuel is plentiful.

One of the more feared aspects of any nuclear blast is that of radiation. In larger nuclear weapons, immediate radiation will spread over an area smaller than that of the blast radius. Smaller weapons, however, may utilize radiation as its greatest damaging effect (i.e., Hiroshima and Nagasaki). May Japanese suffered injuries and died from immediate radiation. The medical study of radiation is still under much controversy to this day, but it seems that even small amounts of radiation are enough to kill living tissue (hence its very cautious use in chemotherapy).

Radioactive fallout in itself is a frightening phrase, as it should be. Radioactive fallout refers to material that is "scooped up" in the blast and made radioactive by the explosion. Those materials in the neck of the mushroom cloud will stay airborne for a matter of minutes and fall to the surface relatively close to where they were taken. Local weather conditions can effect the damage of the blast by carrying those radioactive particles in the head of the cloud for greater distances, which will cause more damage to populations that would have otherwise been relatively unaffected by the initial blast. Where it seems that rain would prove to mitigate such ranges, the rain itself can become radioactive, which results in a "hot spot", because the area in which that rain falls will become more radioactive.

Information taken from "The Atomic Archive" via Google.

If you marked out on a map of mainland UK, all the viable nuclear-weapon use targets, and then drew in the maximum radii of effect, you crap yourself to see that most of the country was covered in overlapping circles...nowhere to run

However, I'd think that NW use would be deployed primarily ain an anti-electronics infrastructure capacity.

A single high-altitude airburst to knock out all sophisticated weaponry, detection, and communications as the ultimate threat. Failure to capitulate results in impact-effect

[edit on 31-3-2009 by citizen smith]

Originally posted by citizen smith
If you marked out on a map of mainland UK, all the viable nuclear-weapon use targets, and then drew in the maximum radii of effect, you crap yourself to see that most of the country was covered in overlapping circles...nowhere to run

However, I'd think that NW use would be deployed primarily ain an anti-electronics infrastructure capacity.

A single high-altitude airburst to knock out all sophisticated weaponry, detection, and communications as the ultimate threat. Failure to capitulate results in impact-effect

[edit on 31-3-2009 by citizen smith]

But wouldn't it be COOL to witness something like that? WHO OF US CAN SAY, "I saw a nuke detonate."?

Originally posted by MajesticJax
But wouldn't it be COOL to witness something like that? WHO OF US CAN SAY, "I saw a nuke detonate."?

No, it wouldn't be cool...it would be bloody terrifying!

I was made to watch Threads with me mam to educate and make me aware of the world I was growing up in, when it was first aired on UK tv...it scared me then and it still scares me today


[edit on 31-3-2009 by citizen smith]

Part III
There are five classifications that are used to (very broadly) describe nuclear blast types. They are as follows:

High-Altitude - The explosion occurs roughly at 19 miles or higher, and does not touch the surface at all.

Air - The explosion occurs below 18.94 miles (100,000 feet) in the atmosphere, but is too high to touch the ground.

Surface - The explosion occurs at or near the surface. A surface burst that doesn't actually touch the ground is classified as a surface burst when the explosion creates effects that are similar to an actual surface explosion.

Underground or Underwater - These terms are used for buried or submerged explosions, respectively.

Fractions of a second after the device is detonated, the heat from the fireball creates a high-pressure wave of air. This shockwave is pressed out from the explosion at mind-torquing speeds. The shock front is the area of air furthest from the blast. Behind it, the air moves as a very fast wind.

At the shock front, an almost instantaneous jump in pressure results. A combination of this effect (called overpressure) and the dynamic pressure against the objects facing the blast create blast damage. When the actual shockwave arrives, both the overpressure and dynamic pressure come to a climax. From that point, over a period ranging from fractions of a second to several seconds, the pressure depresses (depending on the strength and yield of the bomb).

Now we touch a bit more on the subject of overpressure. For sake of understanding, let us use a 1-megaton bomb as our example. When the fireball of that bomb has reached its maximum size of 5,700 feet across (1.08 miles), the shock front will be approximately three miles ahead after ten seconds. Forty seconds later, the fireball will no longer be visible, and the blast wave will have traveled approximately twelve miles. It will then be traveling at approximately 784 miles per hour.

Normal atmospheric pressure on Earth is slightly less than 15 psi. Overpressure uses its own symbol, known as "Δp". At 50 Δp, the wind travels at a maximum of 934 mph, which is 5 times stronger than the winds of Hurricane Katrina. At 5 Δp, entire cities can be destroyed, with heavy damage resulting in areas hit with 3 Δp. Outside of 3 Δp, the chance of fatalities from the overpressure diminishes significantly.

Humans are surprisingly resilient. At pressures less than 40 Δp, lethal effects are not commonly noted. However, structures collapse at just 3 Δp, which can obviously result in injuries and/or death. Also, the extremely high winds (which clock at 70 miles per hour at just 2 Δp) can cause humans to become airborne, which can obviously cause injuries, if not death. As graphic as it is, blast winds can also tear away burned flesh from the thermal radiation, augmenting wounds that may have otherwise been more easily treated.

Now to the concept of the "mach stem". When an explosion occurs above the ground, two waves are created. The first, called the "incident wave", travels slower than wave created from reflecting off the surface of the earth (thus called the "reflected wave") due to the fact the reflected wave is traveling through air already moved by the first wave. When both of these waves combine, they form what is called the "mach stem", which contains twice the overpressure of the direct wave front.

Like a tsunami, a mach stem starts out relatively small in height. However, as it gains momentum and moves outward, its height increases steadily. Going back to our 1-megaton explosion, after forty seconds, the mach stem will be ten miles from the hypocenter, and the overpressure will have decreased to approximately 1 Δp.

Information taken from "The Atomic Archive" via Google.

Just something an alien civilization on another planet would recognize. And send "investagory" craft to "investigate".

Let me add: "the" phenomenon started happening when we started testing nukes.

Space/Time/Spirit????

[edit on 31/3/09 by MajesticJax]

Part IV

Within a nuclear blast, heat is largely used to detonate bomb materials. However, as the thermal radiation expands, temperatures within the fireball can reach up to 1,000,000° Celsius.

There are two "pulses" that are emitted from a nuclear blast. The first lasts for a tenth of a second, and consists of ultraviolet radiation. The second pulse carries the vast majority (approximately 99%) of the thermal radiation, and lasts for several seconds. For those dropping or detonating the bomb, optimal conditions include clear skies, because clouds or smoke in the air can reduce the effects of thermonuclear radiation.

The time at which a fireball comes after the detonation is measured in fractions of a millionth of a second, and immediately the fireball begins to grow and engulf the air around it. Because of its increasing mass, the fireball actually decreases in temperature. The fireball simultaneously rises like a hot-air balloon. To give you an idea, within 0.007 seconds, our 1-megaton explosion will have a fireball that is 440 feet across. Almost exactly 9.993 seconds later, the fireball will have grown to over a mile, at 5,700 feet across. At that point, it rises at a rate of 250 to 350 feet per second. After one minute, the fireball no longer emits visible heat and light, but has risen roughly 4.5 miles from the hypocenter.

The infamous mushroom cloud is formed when the fireball increases in size and cools down, causing the vapors to condense. The cloud is full of weapon debris, as well as small droplets of water from the air sucked in during the blast.

The cloud can have various appearances, which partly depend upon the "afterwinds", or the updraft that causes debris to be sucked into the cloud. Almost all clouds are reddish immediately after their creation due to the nitrous acid and nitrogen oxides present. With the passage of time, particles of water cause the cloud to take on a more conventional grayish cloud color.

Again, atmospheric conditions (as well as the specifics of the bomb) will affect the height of the cloud. Generally speaking, if the cloud reaches six to eight miles above the Earth, it will spread out. However, if sufficient energy remains, the cloud will rise to the more stable areas of the stratosphere. After ten minutes, the cloud will probably reach its maximum height and is said to be "stabilized". It will grow laterally, where it will take on its namesake shape, and may be visible for an hour or more before it is carried away by natural winds and grafts itself into surrounding clouds.

After the initial blast, the majority of deaths that will take place afterward are caused by firestorms, flashburn injuries, radiation poisoning, and the ensuing panic.

For more reading, visit the Atomic Archive.

Originally posted by MajesticJax
But wouldn't it be COOL to witness something like that? WHO OF US CAN SAY, "I saw a nuke detonate."?

Does that mean you're volunteering as a human shield when we get to TEOTWAWKI?

In regards to a nuclear explosion in Sit X there are quite afew variables.

1) Type of blast. Im not talking about megatons although thats important but rather the situation. Isolated blast like a terrorist incident or rather an all out exchange between say the Soviets and the US.

All out exchange, would mean any of us in urban areas are done by and large. In the San Francisco bay area we are ringed with primary targets from San Jose and San Fran, to Moffett Field, Lawrence Livermore Nuclear labs, the FEMA COG site in Sonoma etc. I do not expect to get out.

In the even of an isolated blast that is much more survivable. San Francisco is far enought away to survive the primary blast and perhaps give you time to put some distance given the usual wind patterns

The old attage: location, location, location

2) Shelter. Can you find shelter that will provide some protection against fallout. Ive looked at old civil defence articles and the like and basically any shielding is better than nothing. We have a targeted room that has tiled walls and is in the center of the house. Piling up crap in rooms can provide some shelter but not much. Underground is the way to go IMHO but how many people have that ability?


One question I have. Hospital MRI scanners are basically inside a room that is a giant Faraday cage. Is it enough to shield stuff against a EMP type event? Just curious

3) Can you get out if in a high risk area? That a tough one. Terrorist incident will provide no warning but a nuclear exchange should have a build up of tension that if you are prepared and have a plan you may be able to get out with alot of your stuff.

Very interesting and very scary.
I have been wondering about nukes and how far I am from major cities.
Thanks for this info.

I live in NYC, and my primary office is in lower Manhattan just across the street from Federal Plaza (a very large federal office building in New York that houses most of the federal agencies like FBI). I am about a quarter mile north of Wall Street, and a couple of blocks from all the federal and state court houses in Manhattan. My practice (criminal defense attorney) also frequently takes me to downtown Brooklyn. This is just across the Brooklyn Bridge.

I guess if a terrorist set off a nuke anywhere in my vicinity, I am royally screwed. I mean a blast that is in excess of a mile would fry a huge part of Manhattan and might even have a devastating effect on downtown Brooklyn.

I don't expect a nuke coming from another country via missile, of bomber. I don't think anyone (Iran included) would be crazy enough to launch against the US. They would be completely annihilated by the retaliatory strike.

Its far more likely that a terrorist would sneak it in.

Originally posted by FredT




One question I have. Hospital MRI scanners are basically inside a room that is a giant Faraday cage. Is it enough to shield stuff against a EMP type event? Just curious

I recently did some work in a PET scan unit..They were adding a machine and new room..The room was lined with 3/8ths lead faced panels...Is that enough for an EMP?

Originally posted by Redpillblues
I recently did some work in a PET scan unit..They were adding a machine and new room..The room was lined with 3/8ths lead faced panels...Is that enough for an EMP?

I know that EM radiation does not get out. My pager and cell dont work in the CT scanner which is shielded the same way.

We recently installed 3 Tesla MRI and the field is double that of the previous one so Im wondering if it got extra shielding as well.


[edit on 3/31/09 by FredT]

Did some searching and found this thread:

May be of help I off to do some reading


Protecting Yourself from EMP
www.abovetopsecret.com...

Originally posted by citizen smith
If you marked out on a map of mainland UK, all the viable nuclear-weapon use targets, and then drew in the maximum radii of effect, you crap yourself to see that most of the country was covered in overlapping circles...nowhere to run

However, I'd think that NW use would be deployed primarily ain an anti-electronics infrastructure capacity.

A single high-altitude airburst to knock out all sophisticated weaponry, detection, and communications as the ultimate threat. Failure to capitulate results in impact-effect

[edit on 31-3-2009 by citizen smith]

I mentioned something similar to this a while ago about my child-minder's son drawing big circles around local RAF bases circa. 1980. It also ties in with Nirgal's 30 mile fart rule.

My mother never should have given me "When the Wind Blows" to read, gave me nightmares.

Now I'm growing out of my deep-rooted fear of M.A.D. I know that given a bit of common sense and fortunate timing most things are survivable.

Originally posted by citizen smith

Originally posted by MajesticJax
But wouldn't it be COOL to witness something like that? WHO OF US CAN SAY, "I saw a nuke detonate."?

No, it wouldn't be cool...it would be bloody terrifying!

I was made to watch Threads with me mam to educate and make me aware of the world I was growing up in, when it was first aired on UK tv...it scared me then and it still scares me today


[edit on 31-3-2009 by citizen smith]

I remember when it came on TV.
My parents video'd it while they watched it first to 'vet it'.
After it had finished (both parts). My dad wiped the video.
They said it was beyond the pale for kids to see the level of death and misery of nuclear war and the aftermath. Just hope you don't experience it for real we got told.
My mum described it pretty well though.

So we never go to watch it. Just told about it.
I'm glad in a way as its supposed to be more hardcore than '1984' is.
One of the few films to portray nuclear winter though...

I saw the animated one (when the wind blows) and that was pretty stupid and unrealistic IMO.

My Dad told me that Lancashire is vulnerable 'cause of Warton airfield and the Power Stations around the county.

Originally posted by citizen smith
If you marked out on a map of mainland UK, all the viable nuclear-weapon use targets, and then drew in the maximum radii of effect, you crap yourself to see that most of the country was covered in overlapping circles...nowhere to run

However, I'd think that NW use would be deployed primarily ain an anti-electronics infrastructure capacity.

A single high-altitude airburst to knock out all sophisticated weaponry, detection, and communications as the ultimate threat. Failure to capitulate results in impact-effect

[edit on 31-3-2009 by citizen smith]

Most modern nuclewar weapons are air burst types rather than ground burst , also the mega tonnage has been reduced as well by most nuclear users. With the massive improvements in pin point navigation the huge city busters are no longer needed nor used by most forces.

reply to post by WatchRider


Me mam had the foresight to expose me to the horrrors of MAD through Threads, the Raymond Briggs animation, and others, and encouraged me to learn without fear.

I remember the shelves of sweet-jars cached under the stairs of dried pulses, tins and whatnot, the games of building dens in the woods out the back of the house and wild-camping trips, or piling furniture and stuff on top of/around the huge dining table...

God bless her foresight and got her boys ready just in case the SHTF