CONFIDENTIAL Table 1 summarizes some aspects of the target cities. these targets affords a rather general representation. It is apparent that choice of Three are coastal cities and three are inland. Thecities vary in size from 350,000 to 2,200,000. Twocities have relative freedom to move in any direction. Twoare limited to 180-deg movement, and two (for different reasons) are limited to less than 180-deg possible movement. The principal activities of the cities also are varied. TABLE 1 CHARACTERISTICS OF TARGET CITIES City Location Boston Dayton Milwaukee St. Louis San Francisco East Coast Inland Inland Inland West Coast Washington East Coast Population, Movement thous limitations Predominant activity 2200 350 800 1400 2000 270 deg None 180 deg 180 deg Peninsular Port, diversified industry Manufacturing Port, food processing Manufacturing Port, petroleum, food processing 1700 None Government a URBAN COMPLEX AS A TARGET General Population Of the six targets studied, all but one, the San Francisco Bay area, have a single center of population, a point at which the explosion of a single weapon could produce more casualties than an explosion at any other point. In the case of Washington at least, there is no shift in the location of this point from day to night,* although there is a marked increase in density of population around this point during the working day (see Fig. 1). Figure 2 shows by concentric 4-mile bands [designed to correspond to Federal Civil Defense Administration (Fcpa) zones of A, B, C, and D damage for a 10-Mt weapon with a ground zero (az) at the Ellipse, near the White House *] the distribution of day and night populations superimposed on the target area under consideration. traffic lanes leaving each zone. This figure also shows the number of The nighttime (resident) population distributions of the other target areas (Boston, Dayton, Milwaukee, St. Louis, and San Francisco) are shown in Figs. 3 to 7. The numbers in the squares represent thousands of residents within units 2000 by 2000 m each. For each target the centroid of population is indicated. Since the San Francisco Bay area has two population clusters (Oakland and San Francisco), which are separated by water, two population centroids are indicated for this target. Special Populations Because of the importance of physicians in the postattack situation, the distribution of greater Washington area physicians during the day and night was plotted. It was found that although the density of physicians at the center of the city markedly increased during the day, this increase was proportional to the general increase in population density, and as in the population as a whole, there was no shift in the point of highest density from day to night. *Daytime population figures were not available to permit similar comparisons within the other targets. ORO-R-17 (App B) 9