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OCR for page 15
The Medical Implications of Nuclear War, Institute of
Medicine. ~ 1986 by the National Academy of Sciences.
National Academy Press, Washington, D.C.
Possible Fatalities from Superfires
Following Nuclear Attacks
in or near Urban Areas
THEODORE A. POSTOL, PH.D.
Stanford University, Stanford, California
INTRODUCTION
During the period of peak energy output, a 1-megaton (Mt) nuclear
weapon can produce temperatures of about 100 million degrees Celsius
at its center, about four to five times that which occurs at the center of
the Sun.
Because the Sun's surface is only about 6,000°C and it heats the Earth's
surface from a range of more than 90 million miles (about 145 million
km), it should be clear that such a nuclear detonation would be accom-
panied by enormous emanations of light and heat.
So great is the amount of light and heat generated by a 1-Mt airburst,
that if one were to occur at a high enough altitude over Baltimore, observers
in Washington, D.C., might see it as a ball of fire many times brighter
than the noonday Sun. Even if such a detonation were to occur near dawn
over Detroit, out of line of sight because of the Earth's curvature, enough
light could well be scattered and refracted by atmospheric effects for it
to be observed as a glare in the sky from Washington, D.C.
This intense light and heat from nuclear detonations is capable of setting
many simultaneous fires over vast areas of surrounding terrain. These
fires, once initiated, could efficiently heat large volumes of air near the
Earth's surface. As this heated air buoyantly rises, cool air from regions
beyond the vast burning area would rush in to replace it. Winds at the
ground could reach hurricane force, and air temperatures within the zone
of fire could exceed that of boiling water.
15
OCR for page 16
16
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
The ferocious hurricane of fire would also be accompanied by the release
of large amounts of potentially lethal toxic smoke and combustion gases,
creating an environment of extreme heat, high winds, and toxic agents in
target areas.
Although the smoke from these fires has been the subject of considerable
attention, as it is possible that significant climate effects could result from
its sudden injection into the upper atmosphere, there has been no com-
prehensive evaluation of the implications of these fires for those in target
areas.
In this paper, the potential implications of these fire environments on
casualty estimates is assessed.
The standard model for calculating deaths and nonfatal injuries from
hypothetical nuclear attacks assumes that the same casualty rates will occur
at each level of blast overpressure as that which occurred at Hiroshima.
This methodology, which will henceforth be referred to as blast elect, or
simply blast scaling, is the standard methodology used by government
agencies to estimate casualties in nuclear war.
The preliminary analysis presented in this paper indicates that if fire
effects are included in assessments of possible fatalities from nuclear
attacks using megaton or near megaton airbursts in or near urban areas,
about two to four times more fatalities might be expected relative to those
which might be expected from blast scaling calculations.
This enormous increase in projected fatalities is partly a result of the
very large expected range of superfires, which would extend well beyond
that in which large numbers of blast fatalities would be expected, and
partly because of the high lethality in the blast-disrupted and fire-swept
environments within the burning region.
The very great uncertainties in the speculated differences between blast
and fire scaling are due to the great uncertainties in the radius of the
potential fire zone, as well as to uncertainties in the exact nature of the
environments within these zones.
Another feature that emerges from the analysis is that the projected
number of injured requiring medical treatment would be drastically re-
duced relative to that projected by blast scaling, as many injured that
would otherwise require treatment would be consumed in the fires. This
is consistent with the findings of German review commissions which
were set up during World War II to evaluate the effects of large-scale
incendiary raids against their cities and with the findings of the U.S.
Strategic Bombing Survey after World War II.2 Both reviews found that
the ratio of fatalities to injuries was much higher when the effects of
incendiaries, rather than high explosives, was the major source of damage
from air raids.
OCR for page 17
POSSIBLE FATALITIES FROM SUPERFIRES
17
In this paper, the following will be discussed. First, the blast and
incendiary effects that would accompany the detonation of a 1-Mt airburst
will be described. A baseline estimate of the radius of potential incendiary
effects from the airburst will then be established; and the distinctive char-
acteristics of the resulting giant area fires, high winds, and unusually high
average air temperatures will be described. Evidence is presented to show
that contrary to what has been previously believed, 3-5 attacks on lightly
built-up, sprawling American cities, where the amount of combustible
material per unit area is relatively low, could well result in extreme con-
ditions somewhat comparable to those of the firestorms experienced in
Japan and Germany during World War II. Estimates of noxious gas con-
centrations then will be made using data presented in the previous section,
and it will be shown that the combination of these toxic agents within the
fire zone are likely to be lethal to all unprotected individuals. Anecdotal
and medical observations from World War II firestorm experiences will
be reviewed, and a very crude cookie cutter model will be discussed. It
is argued that more sophisticated models are unjustified in view of the
large uncertainties in possible fire radius but that the simplicity of this
model still allows a preliminary assessment of the importance of fire
effects. The currently standard blast effect scaling method will be reviewed
and compared and contrasted with the fire effect scaling method. Projec-
tions of casualties using both blast and fire scaling will then be presented
for airburst antipopulation attacks. This establishes a reference case for
the comparison of casualty projections by both methods and for different
target sets. It will be shown that blast scaling may underestimate fatalities
from airburst attacks in or near urban areas by factors of about two to
four. Casualty projections are then compared for the antipopulation ref-
erence attack and a very limited anti-industrial attack, which is not de-
signed to kill large numbers of people. However, the inclusion of superfires
in casualty predictions indicates that this more limited attack might actually
result in about two to three times more fatalities than that predicted by
the government for the antipopulation attack. This serves to underscore
the need for a better understanding of these weapons effects.
INCENDIARY EFFECTS OF NUCLEAR WEAPONS
In this section, the events associated with the detonation of a 1-Mt
airburst are described. Because the weapons' effects of interest here, blast
and thermal radiation (heat emanating from the fireballs, do not change dras-
tically with yield and because many of the weapons in today's arsenals
are of comparable yield, this discussion will provide background infor
OCR for page 18
18
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
mation that will allow the reader to construct a picture of an urban target
area following a nuclear attack.
When a nuclear weapon is detonated, an enormous amount of energy
is released in an extraordinarily short interval of time. Nearly all of this
energy is initially released in the form of fast-recoiling nuclear matter
which is then deposited into the surrounding environment within hun-
dredths of millionths of a second.
Unlike a comparable chemical explosion, in which almost all the ex-
plosive power is in expanding gaseous bomb debris, more than 95 percent
of the explosive power is at first in the form of intense light. Since this
intense light is of very short wavelength (it is soft x-rays), it is efficiently
absorbed by the air immediately surrounding the weapon, heating it to
very high temperatures creating a "ball" of fire.
Because the early fireball is so hot, it quickly begins to violently expand,
initially moving outward at several millions of miles per hour while it
also radiates tremendous amounts of light and heat. This rate of expansion
slows rapidly, and by the time the fireball begins to approach its maximum
size, its average speed of expansion is no more than 5,000 to 10,000
miles/in (about 8,000 to 16,000 km/h).
During the course of its expansion, almost all of the air that originally
occupies the volume within and around it is compressed into a thin shell
of superheated, glowing, high-pressure gas. This shell of gas, which
continues to be driven outward by hot expanding gases in the fireball
interior, itself compresses the surrounding air, forming a steeply fronted
luminous shock wave of enormous extent and power (see Figure 1A).
By the time a 1-Mt fireball is near its maximum size, it is a highly
luminous ball of more than 1 mile (1.6 km) in diameter. At 0.9 second
after detonation begins, it is at its brightest. Its surface, which masks the
much hotter interior of the fireball from the surroundings, still radiates
two and a half to three times more light and heat than that of a comparable
area of the Sun's surface.
By taking into account atmospheric attenuation (12-mile About 19.3-
km] visibility), at a distance of 6 miles (about 9.7 km), it would be 300
times brighter than a desert Sun at noon; and at 9 miles (about 14.5 km),
it would still be 100 times brighter. Thus, extensive fire ignitions would
accompany such an airburst over an urban/industrial area.
Figure 1 shows the development of a 1-Mt airburst detonated at an
altitude of 6,500 feet (about 2 km) at five distinct points of time during
the process.6
At 1.8 seconds (Figure 1A), the fireball is no longer expanding very
rapidly, although it is still like a giant luminous and buoyant bubble in
the Earth is atmosphere. It has already passed the time of maximum bright
OCR for page 19
POSSIBLE FATALITIES FROM SUPERFIRES
19
ness, and the shock wave has broken away from it, already reaching a
range of more than 0.5 mile (about 0.8 km) from its point of origin.
When the primary shock wave from the explosion reaches the ground
(see Figure 1B), a secondary shock wave is generated by reflection. The
primary and secondary shock waves then propagate outward along the
ground, forming a single vertical shock wave called the reinforced Mach
front (see Figure 1C). The overpressure in this shock is roughly twice that
of either the primary or the secondary shock.
By judicious choice of height of burst, it is possible to maximize the
area over which this Mach front delivers a predetermined level of destruc-
tive overpressure. For the choice of burst height in this example, the area
over which 15 pounds per square inch (psi) or more occurs has been
. .
maxlmlzec ..
Figure 1C shows the situation at roughly 11 seconds after detonation.
The shock wave would be about 3 miles (about 4.8 km) from the point
on the Earth's surface over which the detonation occurred (this point is
called ground zero), and the peak shock overpressure would be 6 psi. In
the next 5 seconds, the shock would reach a range of 4 miles (about 6.4
km) and decay to a peak overpressure of 5 psi.
Figure 2 shows the sequence of events as they might occur at a wood
frame house at a distance of 4 miles. Since the shock wave would take
16 seconds to arrive at the 4-mile range, when the detonation begins, a
bright flash of growing intensity would be observed at the house within
tenths of seconds. Because the shock wave would take a long time to
arrive, this is the only initial indication of a detonation (see Figure 2A).
Hence, sounds and noise levels around the house, at least at this moment,
would be relatively unaltered.
The fireball, of course, continues to grow in brightness. Within 1 sec-
ond, it is at its maximum brightness, appearing 800 to 900 times brighter
than a desert Sun at noon. The tremendous rate of arrival of radiant power
would result in the effusion of black smoke from the front of the house,
as paint would be burned off the wood surfaces (see Figure 2B). If the
building has interior household materials in it, and they are in the line of
sight of the fireball, they would explode into violently burning fires almost
instantly.
Fifteen seconds after the peak in the thermal pulse, the shock wave
arrives (see Figures 2D, 2E, and 2F). Unlike a shock wave of comparable
peak overpressure from a high explosive bomb, which persists for about
0.1 second as it passes, this shock wave persists for nearly 3 seconds. As
a result, it is accompanied by winds of more than 150 miles/in (about 241
km/h). The shock wave therefore would first strike the building and then
envelope it in a region of high-pressure air and high winds. The building
OCR for page 20
20
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
A
1 MEGATON AIR BURST-1.8 SECONDS
~ Nuclear and Thermal Radiation
/~ Fireball
A/ Primary Blast Wave Front
1 Mt I I I I I I I
Miles 0 1 2 3 4 5 6
B
1 MEGATON Al R BURST-4.6 SECONDS
/: aft:: : X~'
,' Nuclear and Thermal Radiation
/ ~ Primary Blast Wave Front
, Reflected Blast Wave Front
0~ t/C/ommencementof Mach Reflection
\~ ~1~/ Overpressure 16 psi
A.. ~
1 Mt I I I I I I I
Miles 0 1 2 3
C
1 MEGATON AIR BURST-11 SECONDS
/
/
~ ........
, ................................. ~
.~ Wind Velocity 180 mph A.......
Nuclear and Thermal Radiation
an\/ Primary Blast Wave Front
Reflected Blast Wave Front
Mach Front
~ Overpressure 6 psi
AL = ;= _
~3
1 Mt
~ I I ~ I I
Miles 0 1 2 3 4 5 6
FIGURE 1 The sequence of events for a 1-Mt airburst detonated at 6,500 feet
(about 2 km) altitude are shown in A through E. This altitude maximizes the
range from ground zero at which the primary and secondary shock waves coalesce
OCR for page 21
POSSIBLE FATALITIES FROM SUPERFIRES
D
Rate of Rise
1 Mt 250 mob
1 MEGATON Al R BURST-37 SECONDS
: -
-
Reflected Blast
Wave Front
_ ~
\
it,
Nuclear Radiation r'''''a'Y clan \ \
, Wave Front \,
of Bomb Resiclue
|~ Mushroom Stem Mach Front
| Overpressure 1 psi
~ Afterwinds Wind Velocity 40 mph ~ I
- ~=
1 Mt r I I l ' ~ ' ~
Miles 0 1 2 3 4 5 6 7 8 9 10
l
1 Mt-Total Thermal Radiation 30 20 8 5
cal/sq cm
r
E
Rate of Rise
1 Mt 130-170 mph
Radioactive
Cloud
1 MEGATON Al R BURST-1 10 SECONDS
Wind Velocity
1 Mt 275 mph
b~ ~AftenNinds
1 Mt r I I ~I ~
Miles 0 1 2 3 4 5 6 7 8 9 10
21
to give a 15-psi peak overpressure on the ground (see text). By adjusting the
detonation altitude to 11,000 feet (about 3,353 m), the 5-psi distance could be
increased from 3.8 to 4.3 miles (about 6 to 7 km), but the 15-psi range would
shrink to near zero. Source: Glasstone (19621.6
OCR for page 22
- ~
::
PHYSICAL EFFECTS AND ENVIRONMENTaL CONSEQUENCES
FIGURE 2 The sequence of prompt nuclear effects as observed at a range of
about 4 miles (about 6.5 km). Light from the fireball begins to illuminate the
structure a few tenths of seconds after the detonation (A). As the brightness of
the fireball increases (B), the front of the house gives off a thick black smoke as
paint is burned off by the heating action of the very intense light. After the paint
is burned off, the house is bathed in light of decreasing intensity as the fireball
rises and cools (C). About 16 seconds after the detonation, the shock wave arrives
(D). As it propagates across the building, the front wall begins to cave in, and
tiles are stripped from the roof. When the building is completely engulfed by the
passing shock wave (E and F), the high pressure that now surrounds the building
crushes the structure, and the high winds cause further damage to the building as
it collapses. Source: Glasstone and Dolan (1977~3 and Glasstone (19621.6
OCR for page 23
POSSIBLE FATaLITIES FROM SUPERFIRES
23
_
_ .
_a~
__
-
~ I_
ad_
ICY
-
OCR for page 24
24
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
thus would be simultaneously knocked down and crushed as the shock
wave propagates past.
Figures 3A and 3B show typical urban residential structures that have
been subjected to overpressures of about 5 psi from nuclear bursts at the
Nevada Test Site. Because these structures were constructed to study the
effects of blast, precautions were taken to prevent them from burning.
The exteriors were painted white to reflect rather than to absorb light from
the fireball, windows facing the explosion were equipped with light-re-
flecting aluminum finish, metal Venetian blinds, and roofs were made of
light gray asbestos cement shingles. Also, there were no utilities (gas
lines, electric lines, stoves, etc.) that could be sources of secondary fires
from blast effects.
Of course, if fires from thermal and secondary blast effects had been
allowed to initiate in these structures, they would clearly burn with great
or. ~
eruclency.
It would take 37 seconds from the time of detonation for the shock
wave to reach a distance of about 9.5 miles (about 15.3 km). At this
distance, 35 to 36 seconds before its arrival, the fireball would be about
100 times brighter than the Sun at noon. This is bright enough to cause
first- or second-degree skin burns on those in line of sight. It is also
possible, but much less certain, that some scattered fires could be set in
very highly combustible items (possibly some dry grass, leaves, or news-
papers, and also interior curtains and other lightweight materials).
When the shock wave finally arrives, it will have a peak overpressure
between 1 and 1.5 psi, which would knock windows (possibly with their
frames) out, along with many interior building walls and some doors (see
Figures 4 through 7 and their figure captions).
By 110 seconds, the characteristic mushroom cloud will have reached
about 7 miles (about 11.3 km) altitude (see Figure 1E). However, from
the ground within the target area, it might be difficult to observe, as great
amounts of dust kicked up by the blast wave and the accompanying high
winds, as well as smoke from the fires initiated by the bright thermal
flash of the fireball, could obscure the vision of those inclined to look.
For those in the target area who are uninjured or still alert enough to be
aware of their surroundings, the drama would not yet be over, as fires
would begin to simultaneously develop and intensify over a vast area.
The situation in the target area therefore would be one of extremely
severe blast damage to a range of 3 to 4 miles (about 4.8 to 6.4 km) from
ground zero and very slowly diminishing levels of serious damage out to
ranges well beyond 10 miles (about 16 km). Streets would be blocked
with debris, water pressure would drop to zero, gas lines would be opened
in places, and power would be off. Essentially all windows would have
been broken, buildings that were not knocked down would have suffered
OCR for page 25
POSSIBLE FATALITIES FROM SUPERFIRES
FIGURE 3 The effects of 5 psi of overpressure from a nuclear detonation are
shown for two structures (A and B) that are typical of those in the United States.
Since the structures were built to study the effects of blast, precautions were taken
to minimize the possibility that fires would be initiated by light from the fireball
or blast disruption effects. For this reason, neither of the buildings contained
utilities of any kind. In addition, the roofs were made of light gray asbestos
shingles, and windows facing the blast were equipped with metal Venetian blinds
with an aluminum finish. Source: Glasstone (1962~.6
OCR for page 62
62
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
A
B
C
100
80
LL
40
80
z 60
Cal
CC
60
20
o
100 .., , ~-. ~1
. , , ~,. ~
.............. Killed + I Injured
2.'...', ''' '''' "'"" " ''""""'""""""""'"" """""""''"'
40
20
o
100
80
60
..............
.. . . .. ..........
An.. ~ .................................
. , ~;;
_ . ~
...................................
. ~.
.......... ..........
......
.......................................
.............................................................
......... ' ' ' ' "'"""''""".
... . .
.. ~, ,.
. ............. ...... ......... . .
A. : Killed
, . . ... . .
~ .... .. ....
:::::::::::::: ::::::-::::::::: -:::::::~::::::::::::::::::::::
Hiroshima Deaths:
Blast Scaled to
Megaton Air Burst
U.S. Office of Technology
~ Assessment
GZ 2 4 6 8 10
12 14 16 18
DISTANCE FROM GROUND ZERO (km)
r
. ........ .
Hiroshima Casualties:
Blast Scaled to
Megaton Air Burst
U.S. Office of Technology
Assessment
' it. ~ ~'~ ~ ~
GZ 2 4 6 8 10 12 14 16 18
DISTANCE FROM GROUND ZERO (km)
U.S. Off ice of Technology
Assessment
40 _
.................. Injured:
20 _ ~
GZ 2 4 6 8 10 12 14 16 18
DISTANCE FROM GROUND ZERO (km)
FIGURE 23 The three graphs show an application of rules used by the OTA to
estimate fatalities and injuries from a 1-Mt airburst over an urban area. The solid
curve in A shows the assumed probability of death as a function of range from
ground zero. The broken curve shows fatality data from Hiroshima scaled by
assuming that the probability of death is purely a function of the peak overpressure
at each range from the detonation. In B similar curves are shown for total cas-
ualties, which is defined to be the sum of those killed and those injured. In C the
OTA rules for those injured (but not killed) are shown as a function of range
from ground zero.
OCR for page 63
POSSIBLE FATALITIES FROM SUPERFIRES
63
The calculations that I performed for the presumed 100-city attack,
using first the OTA/DOD rules and then a blast scaling of Hiroshima data,
gave identical predictions within a few percent. It is therefore clear that
the government rules for estimating fatalities and injures are virtually
indistinguishable from blast scaling of data from Hiroshima.
Figure 24 shows the range dependence of the government's probability
of injury assumptions for a 1-Mt airburst. At selected ranges below the
horizontal axis, the overpressure and thermal energy deposited from the
fireball of a 1-Mt airburst is shown (12-mile [19.3-km] visibility). Above
the axis is the thermal fluence which occurred at a similar overpressure
loo
80
60
Cal
cr
UJ
40 _
20 _
o t
U.S. Office of Technology
Assessment
23 car/cm I
L
13 cal/cm2 1
! 7cal/jcm2 3callcm2
Thermal Fluence at
Same Overpressure at
Hiroshima
GZ 2 4 6 8 10 12 14 16 18
8 psi 5 psi 3 psi 2 psi
DISTANCE FROM GROUND ZERO (km)
1 45 cal/cm2 1 10 cal/cm2
90 cal/cm2 20 cal/cm2
Thermal Fluence and
Blast for One Megaton
Air Burst
FIGURE 24 Some aspects of the physical environment that could influence the
probability of death at different ranges from a ground zero are compared for 1-
Mt and 12.5-kt detonations. The solid curve shows the probability of blast injury
as a function of range from ground zero derived by applying the OTA rules to
the case of a 1-Mt airburst. (These rules are also discussed in the legend to Figure
23 and the text.) The 3-psi range at Hiroshima occurred at about 1.5 miles (about
2.3 to 2.4 km) from ground zero. As indicated on the upper side of the range
axis, the amount of thermal radiation delivered along with the blast was about 7
cal/cm2. Individuals subjected to these effects at Hiroshima would not have been
in the region of mass fire that occurred after the attack. At the 3-psi range for a
1-Mt airburst, about 20 cal/cm2 could be delivered along with the blast. Many
fires would be set at this range, and many additional fires might even be set at
much greater range (perhaps at the 12-km range or greater). Individuals injured
by the 3-psi blast at the 9-km range might therefore have to walk 3 or more km
through a zone heavily damaged by blast and with fires of increasing intensity.
By comparison, an injured individual who survived blast and radiation effects at
ground zero in Hiroshima would have had to walk less than 2 km to escape the
fire zone. It is therefore clear that using blast alone as the criterion for estimating
fatalities could well result in a serious underestimate of the probability of death.
OCR for page 64
64
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
at Hiroshima. Thus, at Hiroshima, about 12 to 13 calories per square
centimeter was deposited at the range at which 5 psi occurred. In contrast,
at the 5-psi range for the 1-Mt airburst, about 45 cal/cm2 occurs.
Because this environment is created at about 6.5 km from the detonation
point and, as shown earlier, it is plausible that a mass fire could rage to
a range of 12 km, it appears unlikely that a simple scaling rule of the
kind used in the OTA/DOD methodology adequately accounts for the
circumstance of those at the 6.5-km range.
Figure 25 shows estimates of fatalities and casualties for the 100-city
reference case. Blast scaling predicts that there would be 14 million to
15 million fatalities and 22 million to 23 million injured.
An alternative postulate, discussed in the previous section, is that su-
perfires of uncertain scale would occur, killing all within a range of 6 to
8 miles (9.5 to 13 km) from each ground zero. For the area outside the
range of the superf~re, then, it can be postulated that the blast injury rules
derived from Hiroshima data apply.
Under these assumptions, the number of outright fatalities increases by
a factor of between 2.5 and 4, resulting in a prediction of from 36 million
to 56 million fatalities, while the number of injured decreases dramatically
to between 3 million and 11 million. This is in accord with German
experiences during World War II, in which medical surveys determined
that incendiary raids always resulted in a much higher ratio of killed to
. .
nJurec ..
The reason for this dramatic change in distribution of fatalities and
injuries can be quickly grasped from Figure 23C. The result of the new
assumption is that many who would be counted as injured in the blast
methodology instead are counted as dead; it also counts uninjured indi-
viduals within the fire zone among the dead as well. The only nonfatal
injured are therefore those who are injured by the effects of the blast but
are outside the perimeter of the superfine.
Even though the scale, ferocity, and effects of these superfires are as
yet highly uncertain, it is not difficult to test the sensibility of this hy-
pothetical casualty estimate.
Because the area covered by such fires is proportional to the square of
the fire radius, if the average fire radius were to increase or decrease by
10 to 15 percent, the result would be an increase or decrease in the affected
area of about 20 to 30 percent. The population density is, to a first
approximation, relatively constant for such small changes in fire radius.44
This means that a 10 or 15 percent increase or decrease in fire radius
results in about a 20 to 30 percent increase or decrease in predicted
fatalities.
Thus, the minimum postulated superfire radius used in the calculations
OCR for page 65
POSSIBLE FATALITIES FROM SUPERFIRES
80
70
60
50
LL 40
of
o
' 30
-
20
10
o
100-Mt ATTACKS
Blast
///
8-Mile
Fire Radius
,...
Blast
8-Mile
Fire Radius
~:~
. . . i
..............
.......
. .
....
....
.~1
.........................
...........
.........
.......
........ ...
ANTI-POPU LATION
65
ANTI-MI LITARY-INDUSTRIAL
FIGURE 25 The potential effects of differing assumptions about the causes of
fatalities and injures. A reference attack that assumes that a single 1-Mt detonation
occurs over the population center of each of the 100 largest metropolitan areas
is used to determine the potential significance of differing fatality and injury rules.
When only blast scaling from Hiroshima is used to estimate fatalities and injures,
about 14 million fatalities and 23 million injured are projected. If it is assumed
that mass fires kill everyone within 6 miles (about 9.7 km) of the ground zeros
and injures beyond that range occur because of blast at the same rate as that
which occurred at Hiroshima, 33 million would be killed and 12 to 13 million
would be injured. If the fire zone extends to 8 miles (about 12.9 km) instead, 56
million would be killed and 6 to 7 million would be injured. Similar results are
also shown for a reference attack that does not seek to kill population but only
attempts to destroy 100 of the most important industrial facilities that would
provide military products that could directly support a war effort.
summarized in Figures 25 and 26 (6 miles or 9.5 km) would have to be
reduced by a factor of somewhat less than the square root of two before
predictions of fatalities could be similar to those of blast scaling metho-
dologies.
High survival rates at a range of about 4 miles (6.5 km) would therefore
OCR for page 66
66
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
be required. At this range, however, the thermal fluence from the fireball
would be about 45 cal/cm2, which is enough to set almost any interior
household material in line of sight of the fireball on fire immediately
(Figure 2B shows the emission of smoke from the front of a wood frame
house from 25 cal/cm21.
If, instead, it is assumed that all those who are not injured by blast
could miraculously escape the hostile effects of near-hurricane-force winds
and air temperatures above that at which water boils, and only those who
are injured according to the blast scaling rules shown in Figure 23C die
in superf~res of radius 6 to 8 miles (9.5 to 13 km), then the number of
deaths would increase by a factor of around two, to 27 million to 33
million.
It is therefore difficult to see how casualty rules that do not include the
hostile effects of mass fires over such vast areas can result in projections
more plausible than even those that follow from the preliminary specu-
lations contained in this study.
COMPARISON OF OTHER TARGET SETS WITH THE
REFERENCE CASE
Daugherty, Levi, and van Hippel44 have made a very complete and
uniquely systematic study of possible fatalities and injuries from nuclear
attacks against the United States. They have not only systematically ex-
amined a wide range of possibilities by varying the assumptions about the
biological consequences of given nuclear environments (for example, var-
iations in the 50 percent lethal dose [LDso] for radiation exposure) and
the behavior of individuals within these environments (how fallout pro-
tection factors, and hence casualties, differ if sheltered people make short
excursions from their shelters), but they have also examined the potential
consequences of plausible variations in the nuclear environment itself (how
injury and fatality estimates vary if populations are subject to fires as well
as to blast).
Furthermore, they have systematically examined the implications of
their assumptions for different potential target classes on both an individual
and multiply aggregated basis. By doing this, they have created a menu
of possibilities from which analysts or decision makers may choose to
contemplate, or to reject as implausible, any of a wide range of potential
nuclear attacks.
This kind of analysis is, so far, absent from studies and results of studies
published by government agencies.
Two interesting reference cases studied by Daugherty et al.44 are note-
worthy:
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POSSIBLE FATALITIES FROM SUPERFIRES
67
1. An attack of 100 single 1-Mt airbursts on 100 U.S. urban centers.
2. An attack of 101 nuclear airbursts on 101 key military-industrial
targets.
As noted by Daugherty et al., because the first reference case has no
areas of overlap from the effects of multiple weapons detonations, the
100-city reference case provides a baseline of analytic interest for com-
parison with other cases in their menu of possibilities.
In addition, if the reference case is calculated using blast scaling casualty
rules derived from data following an attack on a city center (Hiroshima),
an unambiguous estimate of the potential significance of fire effects is
established.
The second reference case is of interest relative to the first since it
provides just such a comparative case from their menu.
This attack is of interest not only because of its central role in many
policy statements and deliberations but also because it does not target
population per se. Instead it uses essentially the same number of warheads
(101 versus 100) to attack a small number of very-high-value military-
industrial end product facilities, and therefore represents what some might
argue is a minimal attack that could quickly interrupt U.S. conventional
war production capabilities.
As shown in Figure 26, if I assume that the 100 detonations are airbursts
of 1-Mt yield and that the hypothesized superfire casualty rules of the
previous section apply, 25 million to 37 million deaths and 2 million to
7 million injured would result. Thus, if fires kill substantial numbers of
people in target areas, the attack that does not target population per se
might result in the death of between 1.5 and 2.5 times more people than
the blast scaling would predict for the antipopulation attack of a similar
size.
It is also of interest to examine the potential effects of choice of weapon
yield. If the rules for guessing the radius of superfire are scaled by as-
suming that the fire radius occurs at the 10-cal/cm2 range (12-mile t19.3-
km] visibility), then Figure 27 shows the predicted results for the anti-
industrial attack, assuming that the attack is instead executed with 101
weapons of either 500- or 100-kiloton (kt) yield.
In this case, the SOO-kt attack would kill 23 million people, 1.5 times
that predicted by blast scaling for the antipopulation reference attack, and
the 100-kt attack would kill about 8 million people, about two-thirds that
predicted by the application of blast scaling to the antipopulation reference
attack.
However, it is noteworthy that the fire radius derived for the 100-kt
weapon is about 4.5 km, and the already speculative cookie cutter fire
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68
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
80
70
60
ILL
a 50
o
LL
o 40
En
lo
o
J
30
20
10
o
100M' ATTACKS
I Juries
Deaths
ANTI-MI LITARY-INDUSTRIAL
ANTI- 8-Mile
POPU LATION Fire Radius
Blast
Only
Smile
Fire Radius
.~
FIGURE 26 Some of the results shown in Figure 25 are rearranged to illustrate
that when the proposed alternative method of assessing casualties is applied to
attacks aimed at industrial facilities rather than population centers, the result could
be greater casualties than in the antipopulation attack. Since such attacks have
sometimes been proposed as relatively limited, and hence more sensible and more
plausible than antipopulation attacks, this comparison serves to underscore the
potentially misleading character of such arguments.
model is still more speculative, as it is more likely that many of those
who would not have been severely injured would have some chance to
attempt to escape the fire region.
CONCLUSION
During World War II the extraordinary power of science was turned to
building a weapon that could create energy densities and temperatures
comparable to those that normally exist in the interiors of stars. Today,
OCR for page 69
.
POSSIBLE FATALITIES FROM SUPERFIRES
80
70
60
50
CL
o
LL
o 40
An
a
o
J
30
20
10
69
-ANTI-POPULATION
1 _
-
:
100 1-Mt
Weapons
Blast
Injuries
Deaths
ANTI-MILITARY-INDUSTRIAL
100 0.5-Mt Weapons
Fire Scaling
L
100 0.1 -Mt Weapons
Fire Scaling
FIGURE 27 The effects of applying the hire casualty rules discussed in the
legend to Figure 25 and the text to attacks that utilize weapons of lower yield.
The predicted casualties when 100 0.5-Mt weapons are substituted for 1-Mt weap-
ons are only slightly diminished. When 0.1-Mt weapons (100 kt) are substituted,
casualties drop significantly. It should be noted, however, that for these much
lower yield detonations, blast scaling from Hiroshima data may be no less un-
certain than alternative rules discussed in this paper.
the results of those and subsequent efforts have given us weapons with
effects that are of vast and nonintuitive scales.
One of these effects is superfires; they would accompany nuclear det-
onations in or near urban areas and might result in two to four times as
many fatalities as that predicted by standard government blast scaling
rules.
The effects of such fires, while recognized by many during and at the
end of World War II, has remained an issue of discussion and research
only among a small group of dedicated researchers. As such, an under
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70
PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
standing of their effects and the possible scale of unpredictable conse-
quences that could accompany the use of nuclear weapons in many
applications remains poorly understood, or absent, from the cognition of
planners and decision makers. Without this understanding, the probability
of misjudgment and miscalculation could be considerable.
NOTES
~Bond, H., ed. 1946. Fire and the Air War. National Fire Protection Association.
2The U.S. Strategic Bombing Survey. 1946. Washington, D.C.: U.S. Government Print-
ing Office.
3Glasstone, S., and P. J. Dolan, eds. 1977. The Effects of Nuclear Weapons. Report no.
0-213-794. Washington, D.C.: U.S. Government Printing Office.
4Federal Emergency Management Agency. 1982. Attack Environment Manual. CPG-2-
1A2. Washington, D.C.: Federal Emergency Management Agency.
sDefense Civil Preparedness Agency. 1973. DCPA Attack Manual. CPG-2-lA1. Wash-
ington, D.C.: Department of Defense.
6Glasstone, S., ed. 1962. The Effects of Nuclear Weapons. Washington, D.C.: U.S.
Government Printing Office.
7Brode, H. L., and R. D. Small. 1983. Fire Damage and Strategic Targeting. PSR Note
567. Los Angeles, Calif.: Pacific-Sierra Research Corp.
~Hassig, P. J., and M. Rosenblatt. 1983. Firestorm Formation and Environment Char-
acteristics After a Large-Yield Nuclear Burst. Proceedings of the 17th Asilomar Conference
on Fire and Blast Effects of Nuclear Weapons. CONF-8305107, May 30-June 3.
9Brode, H. L., D. A. Larson, and R. D. Small. 1983. Hydrocode Studies of Flows
Generated by Large Area Fires. Proceedings of the 17th Asilomar Conference on Fire and
Blast Effects of Nuclear Weapons. CONF-8305107. May 30-June 3.
Larson, D. A., and R. D. Small. 1983. The Large Urban Fire Environment: Trends
and Model City Predictions. Proceedings of the 17th Asilomar Conference on Fire and
Blast Effects of Nuclear Weapons. CONF-8305107. May 30-June 3.
iiSmall, R. D., and D. A. Larson. 1983. Analysis of the Large Urban Fire Environment.
Proceedings of the 17th Asilomar Conference on Fire and Blast Effects of Nuclear Weapons.
CONF-8305107. May 30-June 3.
i2Small, R. D., D. A. Larson, and H. L. Brode. 1983. Fluid dynamics of large area
fires. In Fire Dynamics and Heat Transfer. J. G. Quintiere, R. L. Alpert, and R. A.
Altenkirch, eds. New York: The American Society of Mechanical Engineers.
i3Brode, H. L., and R. D. Small. 1983. Fire Damage and Strategic Targeting. PSR Note
567. Los Angeles, Calif.: Pacific-Sierra Research Corp.
i4Small R. D., and H. L. Brode. 1980. Physics of Large Urban Fires. PSR Report 1010.
Los Angeles, Calif.: Pacific-Sierra Research Corp.
Larson, D. A., and R. D. Small. 1982. Analysis of the Large Urban Fire Environment:
Part I. Theory. PSR Report 1210. Los Angeles, Calif.: Pacific-Sierra Research Corp.
Larson, D. A., and R. D. Small. 1982. Analysis of the Large Urban Fire Environment:
Part II. Parametric Analysis and Model City Simulations. PSR Report 1210. Los Angeles,
Calif.: Pacific-Sierra Research Corp.
i7Brode, H. L. 1980. Large-Scale Urban Fires. PSR Note 348. Los Angeles, Calif.:
Pacific-Sierra Research Corp.
i8Feldstein, M., S. Duckworth, H. C. Wohlers, and B. Linsky. 1963. The contribution
of the open burning of land clearing debris to air pollution. J. Air Pollut. Control Assoc.
13:(11).
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POSSIBLE FATALITIES FROM SUPERFIRES
71
t9Darley, E. F., F. R. Burleson, E. H. Mateer, J. T. Middleton, and V. P. Osterli. 1966.
Contribution of burning of agricultural wastes to photochemical air pollution. J. Air Pollut.
Control Assoc. 1 1:(12).
20Gerstle, R. W., and D. A. Kemnitz. 1967. Atmospheric emissions from open burning.
J. Air Pollut. Control Assoc.
2~wiersma, S. J. 1975. Characteristics of fires in structural debris. Silver Spring, Md.:
Naval Surface Weapons Center.
22Wilton, C., K. Kaplan, B. Gabrielsen, and J. Zaccor. 1976. Blast/Fire Interaction,
Blast Translation, and Toxic Agents. Final Report, URS 7030-6. Redwood City, Calif.:
URS Research Co. See also note 45.
23Pryor, A. J., D. E. Johnson, and N. N. Jackson. 1969. Hazards of Smoke and Toxic
Gases Produced in Urban Fires. San Antonio, Tex.: Southwest Research Institute.
24Takata, A. N., and T. E. Waterman. 1972. Fire Laboratory Tests Phase II, Interaction
of Fire and Simulated Blast Debris, IITRI-J6217(2). Chicago, Ill.: IIT Research Institute.
2sLonginow, A., T. E. Waterman, and A. N. Takata. 1982. Assessment of Combined
Effects of Blast and Fire on Personnel Survivability. Chicago, Ill.: IIT Research Institute.
26Lee, W., H. C. Leong, C. Jee, and M. Gayle Hershberger. 1966. Design of Tests for
the Effects of Mass Fires on Shelter Occupants. Final Report. Palo Alto, Calif.: Isotopes,
Inc.
27Police President of Hamburg. 1971. Short Version of Report on Experiences of the
Hamburg Fire Department During the Air Attacks from July 24 to August 3, 1943. Reprinted
as Appendix 1 in Fire Fighting Operations in Hamburg, Germany During World War II,
by C. F. Miller, Final Report, URS 7030-6. Redwood City, Calif.: URS Research Com-
pany.
28Christian, W. J., and R. C. Wands, eds. 1972. An Appraisal of Fire Extinguishing
Agents. Proceedings of a Symposium at the National Academy of Sciences, April 11-12.
Washington, D.C.: National Academy of Sciences.
29Goodale, T. 1971. An Attempt to Explore the Effect of High Blast Overpressures on
the Persistence of Smouldering Combustion in Debris. Summary Report, URS 7030-6.
Redwood City, Calif.: URS Research Company.
30Braker, W., and A. L. Mossman. 1971. Matheson Gas Data Book, 5th ed. East Ruth-
erford, N.J.
3~Jacobs, M. B. 1949. The Analytic Chemistry of Industrial Poisons, Hazards, and Sol-
vents, 2nd ed. New York: Interscience Publishers, Inc.
32Jacobs, M. B. 1967. Chemical Analysis XXII, The Analytic Toxicology of Industrial
Inorganic Poisons. New York: Interscience Publishers, Inc.
33Henderson and Haggard. 1943. Noxious Gases and the Principles of Respiration Influ-
encing Their Action, 2nd ed. Oxford, England: Clarendon Press.
34Pryor, A. J., D. E. Johnson, and N. N. Jackson. 1969. Hazards of Smoke and Toxic
Gases Produced in Urban Fires. San Antonio, Tex.: Southwest Research Institute.
35Kehrl, Police President of Hamburg. 1946. Secret Report by the Police President of
Hamburg on the Heavy Raids on Hamburg in July/August 1943, I.O.(t)45 (translated and
published by the United Kingdom Home Office, Civil Defense Department, Intelligence
Branch, Document Number 43097, January 1946).
36Report of the Technical Services Division of the Hamburg Fire Protection Police During
the Major Catastrophe and Summary of Reports on Actions During the Air Attacks on
Hamburg from July 24 to August 3, 1943. 1971. Reprinted as Appendix 2 in Fire Fighting
Operations in Hamburg, Germany During World War II, by C. F. Miller, Final Report,
URS 7030-6. Redwood City, Calif.: URS Research Company.
37Miller, C. F. 1971. Fire Fighting Operations in Hamburg, Germany During World War
II. Final Report, URS 7030-6. Redwood City, Calif.: URS Research Co.
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PHYSICAL EFFECTS AND ENVIRONMENTAL CONSEQUENCES
38Taylor, D. H. 1978. Methodology for Estimating High Intensity Attacks. SAI-77-803-
LJ. La Jolla, Calif.: Science Applications Inc.
39In fact, a fourth raid occurred on August 3, 1943; however, it took place during a severe
thunderstorm. Police reports indicate that the substantial numbers of available fire fighting
forces were not overwhelmed, as was the case in the three previous raids.
It should be kept in mind, however, that the most successful attacks are known to have
been those of highest intensity, since they started so many potentially controllable fires so
quickly, that by the time some fires were put out, others had grown beyond control. The
weather's major contribution could well have been interference with the placement of
bombs, rather than expungement of fires.
In Japan, reports indicate that successful incendiary attacks were made even during periods
of light rain and often within hours of heavier rain. For example, 37 percent of the
Nishinomiya-Mikage area was destroyed in a single raid despite the fact that heavy rain
had fallen for the previous 48 hours.
On the other hand, German cities were much more fire resistant than Japanese (and
incidentally American) cities, as building construction was cellular, relying on internal and
external masonry walls to protect against fire propagation. Hence, in the absence of more
complete data on these events, the effects of weather must be considered to be quite
ambiguous.
40Horatio Bond, private communication. National Fire Protection Association.
4iU.S. Congress, Office of Technology Assessment. 1979. The Effects of Nuclear War.
Washington, D. C.: U. S. Government Printing Office.
42Peter Sharfman, private communication, project director of The Effects of Nuclear War,
U.S. Congress Office of Technology Assessment.
43British Medical Association. 1983. The Medical Effects of Nuclear War. The Report
of the British Medical Association's Board of Science Education. London: John Wiley and
Sons.
44Daugherty, W., B. Levi, and F. von Hippel. Casualties Due to the Blast, Heat and
Radioactive Fallout from Various Hypothetical Nuclear Attacks on the United States. This
volume.
45Bucheim, R. W., and the staff of the Rand Corporation. 1958. Space Handbook:
Astronautics and Its Applications. New York: Random House.
Representative terms from entire chapter:
physical effects
