The Effects of Nuclear War
Chapter II
DETROIT AND LENINGRAD
1 Mt on the Surface in Detroit
Physical Damage
Figure 4 shows the metropolitan area of Detroit, with Windsor, Canada, across the river to the southeast and Lake St. Clair directly east. The detonation point selected is the intersection of I-75 and I-94, approximately at the civic center and about 3 miles [5 km] from the Detroit-Windsor tunnel entrance. Circles are drawn at the 12-, 5-, 2-, and 1-psi limits.
The 1-Mt explosion on the surface leaves a crater about 1,000 feet [300 m] in diameter and 200 feet [61 m] deep, surrounded by a rim of highly radioactive soil about twice this diameter thrown out of the crater. Out to a distance of 0.6 miles [1 km] from the center there will be nothing recognizable remaining, with the exception of some massive concrete bridge abutments and building foundations. At 0.6 miles some heavily damaged highway bridge sections will remain, but little else until 1.3 miles [2.1 km], where a few very strongly constructed buildings with poured reinforced concrete walls will survive, but with the interiors totally destroyed by blast entering the window openings. A distance of 1.7 miles [2.7 km] (12-psi ring) is the closest range where any significant structure will remain standing.
Of the 70,000 people in this area during nonworking hours, there will be virtually no survivors. (See table 4.) Fatalities during working hours in this business district would undoubtedly be much higher. The estimated daytime population of the “downtown” area is something over 200,000 in contrast to the census data of about 15,000. If the attack occurred during this time, the fatalities would be increased by 130,000 and injuries by 45,000 over the estimates in table 4. Obviously there would be some reduction in casualties in outlying residential areas where the daytime population would be lower.
Table 4. - Casualty Estimates
(in thousands)
| Region (mi) | Area (mi2) | Population | Fatalities | Injuries | Uninjured |
|---|---|---|---|---|---|
| 0-1.7 | 9.1 | 70 | 70 | 0 | 0 |
| 1.7-2.7 | 13.8 | 250 | 130 | 100 | 20 |
| 2.7-4.7 | 46.5 | 400 | 20 | 180 | 200 |
| 4.7-7.4 | 102.6 | 600 | 0 | 150 | 450 |
In the band between the 1.7- and the 2.7-mile (5 psi) circles, typical commercial and residential multistory buildings will have the walls completely blown out, but increasingly at the greater distances the skeletal structure will remain standing.
Individual residences in this region will be totally destroyed, with only foundations and basements remaining, and the debris quite uniformly distributed over the area. Heavy industrial plants will be destroyed in the inner part of the ring, but some industry will remain functional towards the outer edge. The debris depth that will clutter the streets will naturally depend on both the building heights and how close together they are spaced. Typical depths might range from tens of feet in the downtown area where buildings are 10 to 20 stories high, down to several inches where buildings are lower and streets broader in the sector to the west and north, In this band, blast damage alone will destroy all automobiles, while some heavier commercial vehicles (firetrucks and repair vehicles) will survive near the outer edges. However, few vehicles will have been sufficiently protected from debris to remain useful. The parking lots of both Cobb Field and Tiger Stadium will contain nothing driveable.
In this same ring, which contains a nighttime population of about 250,000, about half will be fatalities, with most of the remainder being injured. Most deaths will occur from collapsing buildings. Although many fires will be started, only a small percentage of the buildings are likely to continue to burn after the blast wave passes. The mechanics of fire spread in a heavily damaged and debris strewn area are not well understood. However, it is probable that fire spread would be slow and there would be no firestorm. For unprotected people, the initial nuclear radiation would be lethal out to 1.7 miles [2.7 km], but be insignificant in its prompt effects (50 rems) at 2.0 miles [3.2 km]. Since few people inside a 2-mile ring will survive the blast, and they are very likely to be in strong buildings that typically have a 2- to 5- protection factor, the additional fatalities and injuries from initial radiation should be small compared to other uncertainties.
The number of casualties from thermal burns depends on the time of day, season, and atmospheric visibility. Modest variations in these factors produce huge changes in vulnerability to burns. For example, on a winter night less than 1 percent of the population might be exposed to direct thermal radiation, while on a clear summer weekend afternoon more than 25 percent might be exposed (that is, have no structure between the fireball and the person). When visibility is 10 miles [16 km], a 1-Mt explosion produces second-degree burns at a distance of 6 miles [10 km], while under circumstances when visibility is 2 miles [3 km], the range of second-degree burns is only 2.7 miles [4.3 km]. Table 5 shows how this variation could cause deaths from thermal radiation to vary between 1,000 and 190,000, and injuries to vary between 500 and 75,000.
In the band from 2.7 to 4.7 miles [4.4 to 7.6 km] (2 psi), large buildings will have lost windows and frames, interior partitions, and, for those with light-walled construction, most of the contents of upper floors will have been blown out into the streets. Load-bearing wall buildings at the University of Detroit will be severely cracked. Low residential buildings will be totally destroyed or severely damaged. Casualties are estimated to be about 50 percent in this region, with the majority of these injured. There will still be substantial debris in the streets, but a very significant number of cars and trucks will remain operable. In this zone, damage to heavy industrial plants, such as the Cadillac plant, will be severe, and most planes and hangars at the Detroit City Airport will be destroyed.
In this ring only 5 percent of the population of about 400,000 will be killed, but nearly half will be injured (table 4). This is the region of the most severe fire hazard, since fire ignition and spread is more likely in partly damaged buildings than in completely flattened areas. Perhaps 5 percent of the buildings would be initially ignited, with fire spread to adjoining buildings highly likely if their separation is less than 50 feet [15 m]. Fires will continue to spread for 24 hours at least, ultimately destroying about half the buildings. However, these estimates are extremely uncertain, as they are based on poor data and unknown weather conditions. They are also made on the assumption that no effective effort is made by the uninjured half of the population in this region to prevent the ignition or spread of fires.
Table 5. - Burn Casualty Estimates
(1 Mt on Detroit)
| Distance from blast (mi) | Survivors of blast effects | Fatalities (eventual) | Injuries | ||
|---|---|---|---|---|---|
| 2-mile visibility | 10-mile visibility | 2-mile visibility | 10-mile visibility | ||
| (1 percent of population exposed to line of sight from fireball) | |||||
| 0-1.7 | 0 | 0 | 0 | 0 | 0 |
| 1.7-2.7 | 120,000 | 1,200 | 1,200 | 0 | 0 |
| 2.7-4.7 | 380,000 | 0 | 3,800 | 500 | 0 |
| 4.7-7.4 | 600,000 | 0 | 2,600 | 0 | 3,000 |
| Total (rounded) | 1,000 | 8,000 | 500 | 3,000 | |
| (25 percent of population exposed to line of sight from fireball) | |||||
| 0-1.7 | 0 | 0 | 0 | 0 | 0 |
| 1.7-2.7 | 120,000 | 30,000 | 30,000 | 0 | 0 |
| 2.7-4.7 | 380,000 | 0 | 95,000 | 11,000 | 0 |
| 4.7-7.4 | 600,000 | 0 | 66,000 | 0 | 75,000 |
| Total (rounded) | 30,000 | 190,000 | 11,000 | 75,000 | |
These calculations arbitrarily assume that exposure to more than 6.7 cal/cm2 produces eventual death, and exposure to more than 3.4 cal/cm°2 produces a significant injury, requiring specialized medical treatment.
As table 5 shows, there would be between 4,000 and 95,000 additional deaths from thermal radiation in this band, assuming a visibility of 10 miles [16 km]. A 2-mile [3 km] visibility would produce instead between 1,000 and 11,000 severe injuries, and many of these would subsequently die because adequate medical treatment would not be available.
In the outermost band (4.7 to 7.4 miles [7.6 to 11.9 km]) there will be only light damage to commercial structures and moderate damage to residences. Casualties are estimated at 25 percent injured and only an insignificant number killed (table 4). Under the range of conditions displayed in table 5, there will be an additional 3,000 to 75,000 burn injuries requiring specialized medical care. Fire ignitions should be comparatively rare (limited to such kindling material as newspaper and dry leaves) and easily controlled by the survivors.
Whether fallout comes from the stem or the cap of the mushroom is a major concern in the general vicinity of the detonation because of the time element and its effect on general emergency operations. Fallout from the stem starts building after about 10 minutes, so during the first hour after detonation it represents the prime radiation threat to emergency crews. The affected area would have a radius of about 6.5 miles [10.5 km] (as indicated by the dashed circle on figure 4) with a hot-spot a distance downwind that depends on the wind velocity. If a 15-mph wind from the southwest is assumed, an area of about 1 mi [260 hectares]—the solid ellipse shown —would cause an average exposure of 300 rems in the first hour to people with no fallout protection at all. The larger toned ellipse shows the area of 150 rems in the first hour. But the important feature of short-term (up to 1 hour) fallout is the relatively small area covered by life-threatening radiation levels compared to the area covered by blast damage.
Starting in about an hour, the main fallout from the cloud itself will start to arrive, with some of it adding to the already-deposited local stem fallout, but the bulk being distributed in an elongated downwind ellipse. Figures 2 and 3 show two fallout patterns, differing only in the direction of the wind. The contours marked are the number of rems received in the week following the arrival of the cloud fallout, again assuming no fallout protection whatever. Realistic patterns, which will reflect wind shear, a wider crosswind distribution, and other atmospheric varibilities, will be much more complex than this illustration.