Brian Carroll, in the throes of a Cold War flashback, wrote:
> what if a nuclear weapon was aimed at the downtown center of any
> large (million) metropolitan area... say, a Inter-Continental
> Ballistic Missile (ICBM) with a nuclear warhead crashing down,
> ground zero in Manhattan, or San Francisco.
A rather macabre subject, which doesn't appear to have much to do with
design, but in the interests of general information I'll bite:
First Point--
It is unlikely that a nuclear strike by ICBM on a major metropolitan area
would involve just one weapon. Should the Russians (or now the Chinese,
thanks to lax security at Los Alamos) choose to nuke San Francisco via ICBM,
one could reasonably expect 5 to 12 MIRV (multiple independent re-entry
vehicles) to strike in the near vicinity of the target coordinate. Each of
these MIRVs could yield up to a couple of megaTons in explosive power. For
those on the list who don't remember what that means, the yields of nuclear
weapons are measured in terms of equivalent explosive power of so many tons
of TNT (tri-nitro toluene, a high explosive invented originally by none
other than Alfred Nobel). A kiloTon is equivalent to 1,000 tons of TNT
going off in an area around the size of a basketball. A megaTon is the
equivalent of 1,000,000 tons of TNT going off in a similar volume. For
comparison's sake, the bomb dropped on Hiroshima was a 1 kiloTon device.
The Mt. St. Helens volcanic eruption yielded approximately 100 megatons
(though much more dispersed than an atomic blast, thus it resulted in much
less equivalent destruction). Most modern strategic nukes yield around 1 to
5 megatons (per warhead). The most powerful nuke ever built (so far as I
know) would have yielded 50 megaTons from a single warhead if used (though
it obviously never was. It was a low-orbit EMP--eletro-magnetic pulse--bomb
designed specifically by the Soviets to knock out the electronic
infrastructure of the United States at a single blow.).
Now, a MIRV strike on a city would virtually erase it from the face of the
earth, out to a radius of several miles. Imagine the pictures of Hiroshima
following the Little Boy strike: near total devastation. Little was left
standing, but you could still see the remnants of the city. Now, that bomb
yielded only 1/1,000th to 1/10,000th the explosive power of a modern nuke.
So, a strike by a modern MIRV ICBM on San Francisco (for example) would
probably not leave much to be portrayed in picturesquely indignant
photojournalism.
Second Point--
Much more likely than an ICBM strike is the possibility of a sneak attack by
a foreign power or nuclear armed terrorists (foreign or domestic). In this
case, the device would likely be just a single warhead of lower yield
(anywhere from 1 kiloTon to 1 or 2 megaTons depending on the resources of
the attacker). This sort of explosion would likely devastate the core of a
highly populated area, but would not be generally destructive. In the
aftermath of such an attack on San Francisco, it is conceivable that Oakland
would not suffer extensive damage (depending, again, on the size and
location of the blast), though SF itself would be vaporized.
> would skyscrapers fall, toppling ontop of one another like
> dominos? would foundations melt? what if..?
The primary immediate effects of a nuclear bomb on infrastructure are: 1.
Overpressure, and 2. Temperature. Radiation is a significant side effect,
but has little direct impact on structures (just people). Hence, the
"Neutron Bomb," which was designed as a high radiation yield device, could
kill millions without doing substantial damage to infrastructure. Another
side effect with a larger effect on infrastructure is EMP. EMP is a massive
pulse of electro-magnetic radiation which results at the instant of
detonation. EMP destroys any un-shielded electronics instantly, even at a
distance of many, many miles.
Overpressure describes the effect of the massive shock wave which is
generated by an explosive event of great magnitude inside an atmosphere.
Overpressure applies a massive force of atmospheric pressure somewhat (but
not quite) uniformly to the exterior of a structure, to the tune of hundreds
or even thousands of PSI. The typical result is near instant disintegration
of the structure. Bigger bombs equal more overpressure intensity. MIRVs
distribute overpressure more evenly, resulting in more widespread
destruction. So, even without the heat, all buildings (except hardened
targets) within a half-mile of the blast center would be blown to (high
velocity) splinters.
The temperature effects of nuclear bombs are more intuitively understood.
When a fission or fusion explosion occurs, bazillions of joules are dumped
into the surrounding environment as some miniscule amount of matter is
converted directly into energy according to E=MC^2. This energy is
liberated across a wide spectrum (all the way up into the gamma ray band),
but most of it comes off as heat. At the moment of detonation, a nuclear
explosion heats its immediate surroundings (within a few-foot radius) to a
temperature hotter than the sun (millions of degrees Kelvin). This heat
then quickly disperses according to the inverse square law. Even then, the
heat is so great that it causes spontaneous ignition of wood and fabrics at
a substantial distance from the blast (a mile or more, depending). Closer
in, steel and concrete melt or even burn.
So, a nuclear blast by a modern weapon in a metropolitan area would leave
little left but shadows burned into the ground, vitrified building
fragments, a massive plume of smoke, and millions of dead people. That's
not a very pleasant thing to consider.
> has there been any research into the effects of nuclear weaponry
> and architecture to date- or has the measely fallout shelter been
> a best guess at nuclear defense... is there no defense to be had?
Yes. The DoD financed a bunch of studies from the 1950s through the 1980s
to study the effects of nuclear weapons on built up areas. I believe most
of them are still available to the public in local libraries (though you may
have to search for them, such reading not being very popular in our
so-called "post-nuclear" era.)
Critical military facilities are designed to withstand a direct attack by
low to medium yield nuclear weapons. My structural engineering professor in
arch. school once pointed out to us that you can design a building to
withstand any possible earthquake--so long as you don't care how much it
costs or whether it has any windows. The same thing goes for nuclear
attacks. NORAD headquarters in Colorado is designed to take some really
serious punishment before its vessels are breached. Indeed, it's likely
that the people inside would be reduced to jelly by the pounding it would
take to crack that facility open with standard weapons. Of course, such
facilities have a limited life span, since your opponent will figure out a
way to break it as soon as you've made it (one earth-penetrator missile with
a medium-yield nuke could probably destroy the NORAD facility by surgical
strike). Every fortress prompts the creation of new "fortress crackers."
This evolutionary development of technologies and techniques has been going
on for most of human history, and is unlikely to stop any time soon. This
is one systemic reason why the best defense is ALWAYS a good offense.
"Peace through strength," may sound trite and paranoid, but it has the
advantage in that it works where nothing else does.
Most so-called "bomb shelters" are not really designed to withstand primary
blast effects. Rather, they are designed to withstand secondary and
tertiary effects, such as fallout and radiation. If you build a concrete
vault under a building, and that building is caught within a quarter- or
half- mile of a major nuclear detonation, its inhabitants will be no better
off than someone standing on the street.
However, the primary blast area is limited, so those in shelters outside
that radius would be substantially better off than if they were unprotected.
Thus, they are valuable if you can get to one in time. A terrorist bomb,
especially, would be very likely to be a so-called "dirty" device for many
reasons, two of which are:
A. Making "efficient" nuclear weapons takes an enormous amount of technical
sophistication, skill, and testing. A terrorist bomb would likely be
inefficient and untested, resulting in an incomplete fissioning or
fusioning, and thus causing much fissionable material to be blown out of the
device instead of being consumed in the reaction. This would make the
fallout from the explosion highly radioactive.
B. The device would likely be detonated on the ground, instead of in the air
(most nukes do more damage with an "air burst" because of maximized
overpressure, thus the major powers design for detonation a ways above
ground). Ground bursts cause much more material to be pulverized and thrown
up into the air, thus increasing fallout by many times.
So, in reality, fallout shelters are more important now than ever, if you
operate under the assumption that some homicidal crackpot with a political
axe to grind will eventually get hold of one of these weapons (which seems
inevitable, in my opinion).
Similarly, Americans have become very complacent about the threat of nuclear
warfare, which is probably greater today than it has ever been in our
history. A few years ago, the Chinese foreign minister threatened to nuke
Los Angeles over the Taiwan Crisis, and we seemed to just shrug it off like
he wasn't serious. As Russia destabilizes and succumbs to virulent
nationalism, that threat is compounding.
[and, of course, I live right in the downtown area of a primary target, so I
won't be around to say "I told you so."] ;-)
> what if a nuclear weapon was aimed at the downtown center of any
> large (million) metropolitan area... say, a Inter-Continental
> Ballistic Missile (ICBM) with a nuclear warhead crashing down,
> ground zero in Manhattan, or San Francisco.
A rather macabre subject, which doesn't appear to have much to do with
design, but in the interests of general information I'll bite:
First Point--
It is unlikely that a nuclear strike by ICBM on a major metropolitan area
would involve just one weapon. Should the Russians (or now the Chinese,
thanks to lax security at Los Alamos) choose to nuke San Francisco via ICBM,
one could reasonably expect 5 to 12 MIRV (multiple independent re-entry
vehicles) to strike in the near vicinity of the target coordinate. Each of
these MIRVs could yield up to a couple of megaTons in explosive power. For
those on the list who don't remember what that means, the yields of nuclear
weapons are measured in terms of equivalent explosive power of so many tons
of TNT (tri-nitro toluene, a high explosive invented originally by none
other than Alfred Nobel). A kiloTon is equivalent to 1,000 tons of TNT
going off in an area around the size of a basketball. A megaTon is the
equivalent of 1,000,000 tons of TNT going off in a similar volume. For
comparison's sake, the bomb dropped on Hiroshima was a 1 kiloTon device.
The Mt. St. Helens volcanic eruption yielded approximately 100 megatons
(though much more dispersed than an atomic blast, thus it resulted in much
less equivalent destruction). Most modern strategic nukes yield around 1 to
5 megatons (per warhead). The most powerful nuke ever built (so far as I
know) would have yielded 50 megaTons from a single warhead if used (though
it obviously never was. It was a low-orbit EMP--eletro-magnetic pulse--bomb
designed specifically by the Soviets to knock out the electronic
infrastructure of the United States at a single blow.).
Now, a MIRV strike on a city would virtually erase it from the face of the
earth, out to a radius of several miles. Imagine the pictures of Hiroshima
following the Little Boy strike: near total devastation. Little was left
standing, but you could still see the remnants of the city. Now, that bomb
yielded only 1/1,000th to 1/10,000th the explosive power of a modern nuke.
So, a strike by a modern MIRV ICBM on San Francisco (for example) would
probably not leave much to be portrayed in picturesquely indignant
photojournalism.
Second Point--
Much more likely than an ICBM strike is the possibility of a sneak attack by
a foreign power or nuclear armed terrorists (foreign or domestic). In this
case, the device would likely be just a single warhead of lower yield
(anywhere from 1 kiloTon to 1 or 2 megaTons depending on the resources of
the attacker). This sort of explosion would likely devastate the core of a
highly populated area, but would not be generally destructive. In the
aftermath of such an attack on San Francisco, it is conceivable that Oakland
would not suffer extensive damage (depending, again, on the size and
location of the blast), though SF itself would be vaporized.
> would skyscrapers fall, toppling ontop of one another like
> dominos? would foundations melt? what if..?
The primary immediate effects of a nuclear bomb on infrastructure are: 1.
Overpressure, and 2. Temperature. Radiation is a significant side effect,
but has little direct impact on structures (just people). Hence, the
"Neutron Bomb," which was designed as a high radiation yield device, could
kill millions without doing substantial damage to infrastructure. Another
side effect with a larger effect on infrastructure is EMP. EMP is a massive
pulse of electro-magnetic radiation which results at the instant of
detonation. EMP destroys any un-shielded electronics instantly, even at a
distance of many, many miles.
Overpressure describes the effect of the massive shock wave which is
generated by an explosive event of great magnitude inside an atmosphere.
Overpressure applies a massive force of atmospheric pressure somewhat (but
not quite) uniformly to the exterior of a structure, to the tune of hundreds
or even thousands of PSI. The typical result is near instant disintegration
of the structure. Bigger bombs equal more overpressure intensity. MIRVs
distribute overpressure more evenly, resulting in more widespread
destruction. So, even without the heat, all buildings (except hardened
targets) within a half-mile of the blast center would be blown to (high
velocity) splinters.
The temperature effects of nuclear bombs are more intuitively understood.
When a fission or fusion explosion occurs, bazillions of joules are dumped
into the surrounding environment as some miniscule amount of matter is
converted directly into energy according to E=MC^2. This energy is
liberated across a wide spectrum (all the way up into the gamma ray band),
but most of it comes off as heat. At the moment of detonation, a nuclear
explosion heats its immediate surroundings (within a few-foot radius) to a
temperature hotter than the sun (millions of degrees Kelvin). This heat
then quickly disperses according to the inverse square law. Even then, the
heat is so great that it causes spontaneous ignition of wood and fabrics at
a substantial distance from the blast (a mile or more, depending). Closer
in, steel and concrete melt or even burn.
So, a nuclear blast by a modern weapon in a metropolitan area would leave
little left but shadows burned into the ground, vitrified building
fragments, a massive plume of smoke, and millions of dead people. That's
not a very pleasant thing to consider.
> has there been any research into the effects of nuclear weaponry
> and architecture to date- or has the measely fallout shelter been
> a best guess at nuclear defense... is there no defense to be had?
Yes. The DoD financed a bunch of studies from the 1950s through the 1980s
to study the effects of nuclear weapons on built up areas. I believe most
of them are still available to the public in local libraries (though you may
have to search for them, such reading not being very popular in our
so-called "post-nuclear" era.)
Critical military facilities are designed to withstand a direct attack by
low to medium yield nuclear weapons. My structural engineering professor in
arch. school once pointed out to us that you can design a building to
withstand any possible earthquake--so long as you don't care how much it
costs or whether it has any windows. The same thing goes for nuclear
attacks. NORAD headquarters in Colorado is designed to take some really
serious punishment before its vessels are breached. Indeed, it's likely
that the people inside would be reduced to jelly by the pounding it would
take to crack that facility open with standard weapons. Of course, such
facilities have a limited life span, since your opponent will figure out a
way to break it as soon as you've made it (one earth-penetrator missile with
a medium-yield nuke could probably destroy the NORAD facility by surgical
strike). Every fortress prompts the creation of new "fortress crackers."
This evolutionary development of technologies and techniques has been going
on for most of human history, and is unlikely to stop any time soon. This
is one systemic reason why the best defense is ALWAYS a good offense.
"Peace through strength," may sound trite and paranoid, but it has the
advantage in that it works where nothing else does.
Most so-called "bomb shelters" are not really designed to withstand primary
blast effects. Rather, they are designed to withstand secondary and
tertiary effects, such as fallout and radiation. If you build a concrete
vault under a building, and that building is caught within a quarter- or
half- mile of a major nuclear detonation, its inhabitants will be no better
off than someone standing on the street.
However, the primary blast area is limited, so those in shelters outside
that radius would be substantially better off than if they were unprotected.
Thus, they are valuable if you can get to one in time. A terrorist bomb,
especially, would be very likely to be a so-called "dirty" device for many
reasons, two of which are:
A. Making "efficient" nuclear weapons takes an enormous amount of technical
sophistication, skill, and testing. A terrorist bomb would likely be
inefficient and untested, resulting in an incomplete fissioning or
fusioning, and thus causing much fissionable material to be blown out of the
device instead of being consumed in the reaction. This would make the
fallout from the explosion highly radioactive.
B. The device would likely be detonated on the ground, instead of in the air
(most nukes do more damage with an "air burst" because of maximized
overpressure, thus the major powers design for detonation a ways above
ground). Ground bursts cause much more material to be pulverized and thrown
up into the air, thus increasing fallout by many times.
So, in reality, fallout shelters are more important now than ever, if you
operate under the assumption that some homicidal crackpot with a political
axe to grind will eventually get hold of one of these weapons (which seems
inevitable, in my opinion).
Similarly, Americans have become very complacent about the threat of nuclear
warfare, which is probably greater today than it has ever been in our
history. A few years ago, the Chinese foreign minister threatened to nuke
Los Angeles over the Taiwan Crisis, and we seemed to just shrug it off like
he wasn't serious. As Russia destabilizes and succumbs to virulent
nationalism, that threat is compounding.
[and, of course, I live right in the downtown area of a primary target, so I
won't be around to say "I told you so."] ;-)